diff --git a/docs/03-endpoints/api-admin/projects.md b/docs/03-endpoints/api-admin/projects.md
index 2bf24196df..3f325794dc 100644
--- a/docs/03-endpoints/api-admin/projects.md
+++ b/docs/03-endpoints/api-admin/projects.md
@@ -6,7 +6,7 @@
 # Projects Endpoint
 
 | Scope           | Route                                                          | Operations | Explanation                                                             |
-| --------------- | -------------------------------------------------------------- | ---------- | ----------------------------------------------------------------------- |
+| --------------- | -------------------------------------------------------------- |------------|-------------------------------------------------------------------------|
 | projects        | `/admin/projects`                                              | `GET`      | [get all projects](#get-all-projects)                                   |
 | projects        | `/admin/projects`                                              | `POST`     | [create a project](#create-a-new-project)                               |
 | projects        | `/admin/projects/shortname/{shortname}`                        | `GET`      | [get a single project](#get-project-by-id)                              |
@@ -26,7 +26,8 @@
 | view settings   | `/admin/projects/shortname/{shortname}/RestrictedViewSettings` | `GET`      | [get restricted view settings for a project](#restricted-view-settings) |
 | view settings   | `/admin/projects/shortcode/{shortcode}/RestrictedViewSettings` | `GET`      | [get restricted view settings for a project](#restricted-view-settings) |
 | view settings   | `/admin/projects/iri/{iri}/RestrictedViewSettings`             | `GET`      | [get restricted view settings for a project](#restricted-view-settings) |
-
+| view settings   | `/admin/projects/iri/{iri}/RestrictedViewSettings`             | `POST`     | [set restricted view settings for a project](#restricted-view-settings) |
+| view settings   | `/admin/projects/shortcode/{shortcode}/RestrictedViewSettings` | `POST`     | [set restricted view settings for a project](#restricted-view-settings) |
 
 ## Project Operations
 
@@ -775,7 +776,7 @@ Example response:
 
 ```
 
-### Restricted View Settings
+### Get Restricted View Settings
 
 Permissions: ProjectAdmin
 
@@ -799,7 +800,7 @@ curl --request GET 'http://0.0.0.0:3333/admin/projects/shortname/anything/Restri
 ```
 
 ```bash
-curl --request GET 'http://0.0.0.0:3333/admin/projects/iri/http%3A%2F%2Frdfh.ch%2Fprojects%2F0001/RestrictedViewSettings'
+curl --request GET 'http://0.0.0.0:3333/admin/projects/iri/http%3A%2F%2Frdfh.ch%2Fprojects%2F0001/RestrictedViewSettings' \
 --header 'Authorization: Basic cm9vdEBleGFtcGxlLmNvbTp0ZXN0'
 ```
 
@@ -814,6 +815,49 @@ Example response:
 }
 ```
 
+### Set Restricted View Settings
+
+Both routes take String parameter which sets restricted view size in one of two formats: as an image dimensions or a 
+percentage. The dimensions pattern looks like: `!X,X`, where X is the number representing scaled image dimensions in
+a square, so that the width and height of the returned image are not greater than the requested value.
+Example: `!512,512` means the image's bigger side will be set to 512 pixels, setting the other side respectively to
+image aspect ratio. The percentage pattern looks like: `pct:X`, where X is the number between 1-100 representing the
+percentage the image will be scaled to. Example: `pct:1` means the image will be scaled to 1% of the original image
+size.
+
+Permissions: ProjectAdmin/SystemAdmin
+
+Request definition:
+- `POST /admin/projects/iri/{iri}/RestrictedViewSettings`
+- `POST /admin/projects/shortcode/{shortcode}/RestrictedViewSettings`
+
+Description: Set the project's restricted view
+
+Required payload:
+- `size`
+
+Example request:
+
+```bash
+curl --request POST 'http://0.0.0.0:5555/admin/projects/iri/http%3A%2F%2Frdfh.ch%2Fprojects%2F0001/RestrictedViewSettings' \
+--header 'Authorization: Basic cm9vdEBleGFtcGxlLmNvbTp0ZXN0' \
+--data '{"size": "!512,512"}
+```
+
+```bash
+curl --request POST 'http://0.0.0.0:5555/admin/projects/shortcode/0001/RestrictedViewSettings' \
+--header 'Authorization: Basic cm9vdEBleGFtcGxlLmNvbTp0ZXN0' \
+--data '{"size": "!512,512"}
+```
+
+Example response:
+
+```json
+{
+    "size": "!512,512"
+}
+```
+
 Operates on the following properties:
  - `knora-admin:projectRestrictedViewSize`: the IIIF size value
  - `knora-admin:projectRestrictedViewWatermark`: the path to the watermark image. **Currently not used!**
diff --git a/integration/src/test/scala/org/knora/webapi/e2e/admin/ProjectsADME2EZioHttpSpec.scala b/integration/src/test/scala/org/knora/webapi/e2e/admin/ProjectsADME2EZioHttpSpec.scala
index ad0487bf4f..632557ac84 100644
--- a/integration/src/test/scala/org/knora/webapi/e2e/admin/ProjectsADME2EZioHttpSpec.scala
+++ b/integration/src/test/scala/org/knora/webapi/e2e/admin/ProjectsADME2EZioHttpSpec.scala
@@ -22,7 +22,6 @@ import org.knora.webapi.messages.admin.responder.projectsmessages._
 import org.knora.webapi.messages.admin.responder.usersmessages.UserADM
 import org.knora.webapi.messages.admin.responder.usersmessages.UsersADMJsonProtocol._
 import org.knora.webapi.messages.store.triplestoremessages.RdfDataObject
-import org.knora.webapi.messages.store.triplestoremessages.TriplestoreJsonProtocol
 import org.knora.webapi.messages.util.rdf.RdfModel
 import org.knora.webapi.sharedtestdata.SharedTestDataADM
 import org.knora.webapi.util.AkkaHttpUtils
@@ -39,7 +38,7 @@ import pekko.util.Timeout
 /**
  * End-to-End (E2E) test specification for testing groups endpoint.
  */
-class ProjectsADME2EZioHttpSpec extends E2ESpec with ProjectsADMJsonProtocol with TriplestoreJsonProtocol {
+class ProjectsADME2EZioHttpSpec extends E2ESpec with ProjectsADMJsonProtocol {
 
   private val rootEmail        = SharedTestDataADM.rootUser.email
   private val testPass         = SharedTestDataADM.testPass
@@ -776,5 +775,103 @@ class ProjectsADME2EZioHttpSpec extends E2ESpec with ProjectsADMJsonProtocol wit
         )
       }
     }
+
+    if (baseApiUrl.contains("5555")) "used to set RestrictedViewSize by project IRI" should {
+      "return requested value to be set with 200 Response Status" in {
+        val encodedIri = URLEncoder.encode(SharedTestDataADM.imagesProject.id, "utf-8")
+        val payload    = """{"size":"pct:1"}"""
+        val request =
+          Post(
+            baseApiUrl + s"/admin/projects/iri/$encodedIri/RestrictedViewSettings",
+            HttpEntity(ContentTypes.`application/json`, payload)
+          ) ~> addCredentials(
+            BasicHttpCredentials(rootEmail, testPass)
+          )
+        val response: HttpResponse = singleAwaitingRequest(request)
+        val result: String         = responseToString(response)
+        assert(response.status === StatusCodes.OK)
+        assert(payload === result)
+      }
+
+      "return the `BadRequest` if the size value is invalid" in {
+        val encodedIri = URLEncoder.encode(SharedTestDataADM.imagesProject.id, "utf-8")
+        val payload    = """{"size":"pct:0"}"""
+        val request =
+          Post(
+            baseApiUrl + s"/admin/projects/iri/$encodedIri/RestrictedViewSettings",
+            HttpEntity(ContentTypes.`application/json`, payload)
+          ) ~> addCredentials(
+            BasicHttpCredentials(rootEmail, testPass)
+          )
+        val response: HttpResponse = singleAwaitingRequest(request)
+        val result: String         = responseToString(response)
+        assert(response.status === StatusCodes.BadRequest)
+        assert(result.contains("Invalid RestrictedViewSize: pct:0"))
+      }
+
+      "return `Forbidden` for the user who is not a system nor project admin" in {
+        val encodedIri = URLEncoder.encode(SharedTestDataADM.imagesProject.id, "utf-8")
+        val payload    = """{"size":"pct:1"}"""
+        val request =
+          Post(
+            baseApiUrl + s"/admin/projects/iri/$encodedIri/RestrictedViewSettings",
+            HttpEntity(ContentTypes.`application/json`, payload)
+          ) ~> addCredentials(
+            BasicHttpCredentials(SharedTestDataADM.imagesUser02.email, testPass)
+          )
+        val response: HttpResponse = singleAwaitingRequest(request)
+        assert(response.status === StatusCodes.Forbidden)
+      }
+    }
+    else "used to set RestrictedViewSize by project IRI" ignore ()
+
+    if (baseApiUrl.contains("5555")) "used to set RestrictedViewSize by project Shortcode" should {
+      "return requested value to be set with 200 Response Status" in {
+        val shortcode = SharedTestDataADM.imagesProject.shortcode
+        val payload   = """{"size":"pct:1"}"""
+        val request =
+          Post(
+            baseApiUrl + s"/admin/projects/shortcode/$shortcode/RestrictedViewSettings",
+            HttpEntity(ContentTypes.`application/json`, payload)
+          ) ~> addCredentials(
+            BasicHttpCredentials(rootEmail, testPass)
+          )
+        val response: HttpResponse = singleAwaitingRequest(request)
+        val result: String         = responseToString(response)
+        assert(response.status === StatusCodes.OK)
+        assert(payload === result)
+      }
+
+      "return the `BadRequest` if the size value is invalid" in {
+        val shortcode = SharedTestDataADM.imagesProject.shortcode
+        val payload   = """{"size":"pct:0"}"""
+        val request =
+          Post(
+            baseApiUrl + s"/admin/projects/shortcode/$shortcode/RestrictedViewSettings",
+            HttpEntity(ContentTypes.`application/json`, payload)
+          ) ~> addCredentials(
+            BasicHttpCredentials(rootEmail, testPass)
+          )
+        val response: HttpResponse = singleAwaitingRequest(request)
+        val result: String         = responseToString(response)
+        assert(response.status === StatusCodes.BadRequest)
+        assert(result.contains("Invalid RestrictedViewSize: pct:0"))
+      }
+
+      "return `Forbidden` for the user who is not a system nor project admin" in {
+        val shortcode = SharedTestDataADM.imagesProject.shortcode
+        val payload   = """{"size":"pct:1"}"""
+        val request =
+          Post(
+            baseApiUrl + s"/admin/projects/shortcode/$shortcode/RestrictedViewSettings",
+            HttpEntity(ContentTypes.`application/json`, payload)
+          ) ~> addCredentials(
+            BasicHttpCredentials(SharedTestDataADM.imagesUser02.email, testPass)
+          )
+        val response: HttpResponse = singleAwaitingRequest(request)
+        assert(response.status === StatusCodes.Forbidden)
+      }
+    }
+    else "used to set RestrictedViewSize by project Shortcode" ignore ()
   }
 }
diff --git a/webapi/src/main/scala/dsp/valueobjects/RestrictedViewSize.scala b/webapi/src/main/scala/dsp/valueobjects/RestrictedViewSize.scala
new file mode 100644
index 0000000000..2fb747171b
--- /dev/null
+++ b/webapi/src/main/scala/dsp/valueobjects/RestrictedViewSize.scala
@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2021 - 2023 Swiss National Data and Service Center for the Humanities and/or DaSCH Service Platform contributors.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package dsp.valueobjects
+
+import zio.json.JsonCodec
+
+import scala.util.matching.Regex
+
+/**
+ * RestrictedViewSize value object.
+ */
+sealed abstract case class RestrictedViewSize private (value: String)
+
+object RestrictedViewSize {
+  def make(value: String): Either[String, RestrictedViewSize] = {
+    val trimmed: String = value.trim
+    // matches strings "pct:1-100"
+    val percentagePattern: Regex = "pct:[1-9][0-9]?0?$".r
+    // matches strings "!x,x" where x is a number of pixels
+    val dimensionsPattern: Regex = "!\\d+,\\d+$".r
+    def isSquare: Boolean = {
+      val substr = trimmed.substring(1).split(",").toSeq
+      substr.head == substr.last
+    }
+
+    if (value.isEmpty) Left(ErrorMessages.RestrictedViewSizeMissing)
+    else if (percentagePattern.matches(trimmed)) Right(new RestrictedViewSize(trimmed) {})
+    else if (dimensionsPattern.matches(trimmed) && isSquare) Right(new RestrictedViewSize(trimmed) {})
+    else Left(ErrorMessages.RestrictedViewSizeInvalid(value))
+  }
+
+  def unsafeFrom(value: String): RestrictedViewSize =
+    make(value).fold(s => throw new IllegalArgumentException(s), identity)
+
+  implicit val codec: JsonCodec[RestrictedViewSize] =
+    JsonCodec[String].transformOrFail(RestrictedViewSize.make, _.value)
+}
+
+object ErrorMessages {
+  val RestrictedViewSizeMissing = "RestrictedViewSize cannot be empty."
+  val RestrictedViewSizeInvalid = (v: String) => s"Invalid RestrictedViewSize: $v"
+}
diff --git a/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsMessagesADM.scala b/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsMessagesADM.scala
index b81203ee17..ff00a67498 100644
--- a/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsMessagesADM.scala
+++ b/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsMessagesADM.scala
@@ -11,6 +11,8 @@ import spray.json.DefaultJsonProtocol
 import spray.json.JsValue
 import spray.json.JsonFormat
 import spray.json.RootJsonFormat
+import zio.json.DeriveJsonCodec
+import zio.json.JsonCodec
 import zio.prelude.Validation
 
 import java.util.UUID
@@ -21,6 +23,7 @@ import dsp.errors.ValidationException
 import dsp.valueobjects.Iri
 import dsp.valueobjects.Iri.ProjectIri
 import dsp.valueobjects.Project._
+import dsp.valueobjects.RestrictedViewSize
 import dsp.valueobjects.V2
 import org.knora.webapi.IRI
 import org.knora.webapi.core.RelayedMessage
@@ -346,6 +349,12 @@ case class ProjectRestrictedViewSettingsGetResponseADM(settings: ProjectRestrict
   def toJsValue: JsValue = projectRestrictedViewGetResponseADMFormat.write(this)
 }
 
+case class ProjectRestrictedViewSizeResponseADM(size: RestrictedViewSize)
+object ProjectRestrictedViewSizeResponseADM {
+  implicit val codec: JsonCodec[ProjectRestrictedViewSizeResponseADM] =
+    DeriveJsonCodec.gen[ProjectRestrictedViewSizeResponseADM]
+}
+
 /**
  * Represents an answer to a project creating/modifying operation.
  *
@@ -606,9 +615,7 @@ trait ProjectsADMJsonProtocol extends SprayJsonSupport with DefaultJsonProtocol
     jsonFormat(ProjectKeywordsGetResponseADM, "keywords")
   implicit val projectRestrictedViewGetResponseADMFormat: RootJsonFormat[ProjectRestrictedViewSettingsGetResponseADM] =
     jsonFormat(ProjectRestrictedViewSettingsGetResponseADM, "settings")
-
   implicit val projectOperationResponseADMFormat: RootJsonFormat[ProjectOperationResponseADM] = rootFormat(
     lazyFormat(jsonFormat(ProjectOperationResponseADM, "project"))
   )
-
 }
diff --git a/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsPayloadsADM.scala b/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsPayloadsADM.scala
index 84f33c9c6c..132026f947 100644
--- a/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsPayloadsADM.scala
+++ b/webapi/src/main/scala/org/knora/webapi/messages/admin/responder/projectsmessages/ProjectsPayloadsADM.scala
@@ -79,3 +79,10 @@ object ProjectUpdatePayloadADM {
     )
   }
 }
+
+final case class ProjectSetRestrictedViewSizePayload(size: String)
+
+object ProjectSetRestrictedViewSizePayload {
+  implicit val codec: JsonCodec[ProjectSetRestrictedViewSizePayload] =
+    DeriveJsonCodec.gen[ProjectSetRestrictedViewSizePayload]
+}
diff --git a/webapi/src/main/scala/org/knora/webapi/responders/admin/ProjectsResponderADM.scala b/webapi/src/main/scala/org/knora/webapi/responders/admin/ProjectsResponderADM.scala
index 53b2812527..0abfaf1121 100644
--- a/webapi/src/main/scala/org/knora/webapi/responders/admin/ProjectsResponderADM.scala
+++ b/webapi/src/main/scala/org/knora/webapi/responders/admin/ProjectsResponderADM.scala
@@ -114,7 +114,7 @@ trait ProjectsResponderADM {
   /**
    * Get project's restricted view settings.
    *
-   * @param id the project's identifier (IRI / shortcode / shortname / UUID)
+   * @param id the project's identifier (IRI / shortcode / shortname)
    * @return [[ProjectRestrictedViewSettingsADM]]
    */
   def projectRestrictedViewSettingsGetADM(id: ProjectIdentifierADM): Task[Option[ProjectRestrictedViewSettingsADM]]
@@ -122,7 +122,7 @@ trait ProjectsResponderADM {
   /**
    * Get project's restricted view settings.
    *
-   * @param id the project's identifier (IRI / shortcode / shortname / UUID)
+   * @param id the project's identifier (IRI / shortcode / shortname)
    * @return [[ProjectRestrictedViewSettingsGetResponseADM]]
    */
   def projectRestrictedViewSettingsGetRequestADM(
@@ -646,7 +646,6 @@ final case class ProjectsResponderADMLive(
           )
         )
     }
-
   }
 
   /**
@@ -816,6 +815,9 @@ final case class ProjectsResponderADMLive(
                            )
         // create permissions for admins and members of the new group
         _ <- createPermissionsForAdminsAndMembersOfNewProject(newProjectIRI)
+//      TODO: DEV-2626 add default value here
+//        defaultSize = ""
+//        _          <- setProjectRestrictedViewSettings(id.value, requestingUser, defaultSize)
 
       } yield ProjectOperationResponseADM(project = newProjectADM.unescape)
 
diff --git a/webapi/src/main/scala/org/knora/webapi/routing/admin/ProjectsRouteZ.scala b/webapi/src/main/scala/org/knora/webapi/routing/admin/ProjectsRouteZ.scala
index e154b4cbf0..eca18d3243 100644
--- a/webapi/src/main/scala/org/knora/webapi/routing/admin/ProjectsRouteZ.scala
+++ b/webapi/src/main/scala/org/knora/webapi/routing/admin/ProjectsRouteZ.scala
@@ -15,11 +15,14 @@ import java.nio.file.Files
 
 import dsp.errors.BadRequestException
 import dsp.valueobjects.Iri._
+import dsp.valueobjects.RestrictedViewSize
 import org.knora.webapi.config.AppConfig
 import org.knora.webapi.http.handler.ExceptionHandlerZ
 import org.knora.webapi.http.middleware.AuthenticationMiddleware
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectCreatePayloadADM
+import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM._
+import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectSetRestrictedViewSizePayload
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectUpdatePayloadADM
 import org.knora.webapi.messages.admin.responder.usersmessages.UserADM
 import org.knora.webapi.routing.RouteUtilZ
@@ -84,6 +87,16 @@ final case class ProjectsRouteZ(
           getRestrictedViewSettingsByShortname(shortname)
         case (Method.GET -> !! / "admin" / "projects" / "shortcode" / shortcode / "RestrictedViewSettings", _) =>
           getRestrictedViewSettingsByShortcode(shortcode)
+        case (
+              request @ Method.POST -> !! / "admin" / "projects" / "iri" / iri / "RestrictedViewSettings",
+              requestingUser
+            ) =>
+          setProjectRestrictedViewSizeByIri(iri, request.body, requestingUser)
+        case (
+              request @ Method.POST -> !! / "admin" / "projects" / "shortcode" / shortcode / "RestrictedViewSettings",
+              requstingUser
+            ) =>
+          setProjectRestrictedViewSizeByShortcode(shortcode, request.body, requstingUser)
       }
       .catchAll(ExceptionHandlerZ.exceptionToJsonHttpResponseZ(_, appConfig))
 
@@ -234,6 +247,26 @@ final case class ProjectsRouteZ(
       r                   <- projectsService.getProjectRestrictedViewSettings(shortcodeIdentifier)
     } yield Response.json(r.toJsValue.toString)
 
+  private def setProjectRestrictedViewSizeByIri(iri: IRI, body: Body, user: UserADM): Task[Response] =
+    for {
+      iriDecoded <- RouteUtilZ.urlDecode(iri, s"Failed to URL decode IRI parameter $iri.")
+      id         <- IriIdentifier.fromString(iriDecoded).toZIO.mapError(e => BadRequestException(e.msg))
+      result     <- handleRestrictedViewSizeRequest(id, body, user)
+    } yield result
+
+  private def setProjectRestrictedViewSizeByShortcode(shortcode: String, body: Body, user: UserADM): Task[Response] =
+    for {
+      id     <- ShortcodeIdentifier.fromString(shortcode).toZIO.mapError(e => BadRequestException(e.msg))
+      result <- handleRestrictedViewSizeRequest(id, body, user)
+    } yield result
+
+  private def handleRestrictedViewSizeRequest(id: ProjectIdentifierADM, body: Body, user: UserADM) =
+    for {
+      body     <- body.asString
+      payload  <- ZIO.fromEither(body.fromJson[ProjectSetRestrictedViewSizePayload]).mapError(BadRequestException(_))
+      size     <- ZIO.fromEither(RestrictedViewSize.make(payload.size)).mapError(BadRequestException(_))
+      response <- projectsService.setProjectRestrictedViewSettings(id, user, size)
+    } yield Response.json(response.toJson)
 }
 
 object ProjectsRouteZ {
diff --git a/webapi/src/main/scala/org/knora/webapi/slice/admin/api/service/ProjectsADMRestService.scala b/webapi/src/main/scala/org/knora/webapi/slice/admin/api/service/ProjectsADMRestService.scala
index ec048d3d5c..d19769cf5d 100644
--- a/webapi/src/main/scala/org/knora/webapi/slice/admin/api/service/ProjectsADMRestService.scala
+++ b/webapi/src/main/scala/org/knora/webapi/slice/admin/api/service/ProjectsADMRestService.scala
@@ -13,6 +13,7 @@ import dsp.errors.NotFoundException
 import dsp.valueobjects.Iri.ProjectIri
 import dsp.valueobjects.Project
 import dsp.valueobjects.Project.Shortcode
+import dsp.valueobjects.RestrictedViewSize
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM._
 import org.knora.webapi.messages.admin.responder.projectsmessages._
 import org.knora.webapi.messages.admin.responder.usersmessages.UserADM
@@ -62,6 +63,11 @@ trait ProjectADMRestService {
   def getProjectRestrictedViewSettings(
     identifier: ProjectIdentifierADM
   ): Task[ProjectRestrictedViewSettingsGetResponseADM]
+  def setProjectRestrictedViewSettings(
+    id: ProjectIdentifierADM,
+    user: UserADM,
+    size: RestrictedViewSize
+  ): Task[ProjectRestrictedViewSizeResponseADM]
 }
 
 final case class ProjectsADMRestServiceLive(
@@ -239,6 +245,25 @@ final case class ProjectsADMRestServiceLive(
   def getProjectRestrictedViewSettings(id: ProjectIdentifierADM): Task[ProjectRestrictedViewSettingsGetResponseADM] =
     responder.projectRestrictedViewSettingsGetRequestADM(id)
 
+  /**
+   * Sets project's restricted view settings.
+   *
+   * @param id the project's id represented by iri, shortocde or shortname,
+   * @param user requesting user,
+   * @param size value to be set,
+   * @return [[ProjectRestrictedViewSizeResponseADM]].
+   */
+  override def setProjectRestrictedViewSettings(
+    id: ProjectIdentifierADM,
+    user: UserADM,
+    size: RestrictedViewSize
+  ): Task[ProjectRestrictedViewSizeResponseADM] =
+    for {
+      project <- projectRepo.findById(id).someOrFail(NotFoundException(s"Project '${getId(id)}' not found."))
+      _       <- permissionService.ensureSystemOrProjectAdmin(user, project)
+      _       <- projectRepo.setProjectRestrictedViewSize(project, size)
+    } yield ProjectRestrictedViewSizeResponseADM(size)
+
   override def exportProject(shortcodeStr: String, requestingUser: UserADM): Task[Unit] = for {
     _         <- permissionService.ensureSystemAdmin(requestingUser)
     shortcode <- convertStringToShortcode(shortcodeStr)
diff --git a/webapi/src/main/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepo.scala b/webapi/src/main/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepo.scala
index 6e93af9483..499f465a5b 100644
--- a/webapi/src/main/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepo.scala
+++ b/webapi/src/main/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepo.scala
@@ -7,6 +7,7 @@ package org.knora.webapi.slice.admin.domain.service
 import zio.Task
 
 import dsp.valueobjects.Project.Shortcode
+import dsp.valueobjects.RestrictedViewSize
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM.ShortcodeIdentifier
 import org.knora.webapi.slice.admin.domain.model.KnoraProject
@@ -17,4 +18,5 @@ trait KnoraProjectRepo extends Repository[KnoraProject, InternalIri] {
   def findById(id: ProjectIdentifierADM): Task[Option[KnoraProject]]
   def findByShortcode(shortcode: Shortcode): Task[Option[KnoraProject]] = findById(ShortcodeIdentifier(shortcode))
   def findOntologies(project: KnoraProject): Task[List[InternalIri]]
+  def setProjectRestrictedViewSize(project: KnoraProject, size: RestrictedViewSize): Task[Unit]
 }
diff --git a/webapi/src/main/scala/org/knora/webapi/slice/admin/repo/service/KnoraProjectRepoLive.scala b/webapi/src/main/scala/org/knora/webapi/slice/admin/repo/service/KnoraProjectRepoLive.scala
index fb8f5746d5..187c055085 100644
--- a/webapi/src/main/scala/org/knora/webapi/slice/admin/repo/service/KnoraProjectRepoLive.scala
+++ b/webapi/src/main/scala/org/knora/webapi/slice/admin/repo/service/KnoraProjectRepoLive.scala
@@ -9,6 +9,7 @@ import play.twirl.api.TxtFormat
 import zio._
 
 import dsp.valueobjects.Project
+import dsp.valueobjects.RestrictedViewSize
 import dsp.valueobjects.V2
 import org.knora.webapi.messages.OntologyConstants.KnoraAdmin.HasSelfJoinEnabled
 import org.knora.webapi.messages.OntologyConstants.KnoraAdmin.ProjectDescription
@@ -33,6 +34,7 @@ import org.knora.webapi.slice.resourceinfo.domain.InternalIri
 import org.knora.webapi.store.triplestore.api.TriplestoreService
 import org.knora.webapi.store.triplestore.api.TriplestoreService.Queries.Construct
 import org.knora.webapi.store.triplestore.api.TriplestoreService.Queries.Select
+import org.knora.webapi.store.triplestore.api.TriplestoreService.Queries.Update
 
 final case class KnoraProjectRepoLive(
   private val triplestore: TriplestoreService,
@@ -104,6 +106,15 @@ final case class KnoraProjectRepoLive(
       .query(Select(query))
       .map(_.results.bindings.flatMap(_.rowMap.get("ontologyIri")).map(InternalIri).toList)
   }
+
+  override def setProjectRestrictedViewSize(
+    project: KnoraProject,
+    size: RestrictedViewSize
+  ): Task[Unit] = {
+    val query = sparql.admin.txt
+      .setProjectRestrictedViewSettings(project.id.value, size.value)
+    triplestore.query(Update(query.toString))
+  }
 }
 
 object KnoraProjectRepoLive {
diff --git a/webapi/src/main/twirl/org/knora/webapi/messages/twirl/queries/sparql/admin/setProjectRestrictedViewSettings.scala.txt b/webapi/src/main/twirl/org/knora/webapi/messages/twirl/queries/sparql/admin/setProjectRestrictedViewSettings.scala.txt
new file mode 100644
index 0000000000..ec499c6a93
--- /dev/null
+++ b/webapi/src/main/twirl/org/knora/webapi/messages/twirl/queries/sparql/admin/setProjectRestrictedViewSettings.scala.txt
@@ -0,0 +1,35 @@
+@*
+ * Copyright © 2021 - 2023 Swiss National Data and Service Center for the Humanities and/or DaSCH Service Platform contributors.
+ * SPDX-License-Identifier: Apache-2.0
+ *@
+
+@import org.knora.webapi.IRI
+@import dsp.valueobjects.RestrictedViewSize
+
+@*
+ * Sets project restricted view settings.
+ *
+ * @param iri project's IRI.
+ * @param size project's restricted view size.
+ *
+ *@
+@(iri: IRI,
+  size: String)
+
+PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
+PREFIX knora-admin: <http://www.knora.org/ontology/knora-admin#>
+
+WITH <http://www.knora.org/data/admin>
+DELETE {
+	<@iri> knora-admin:projectRestrictedViewSize ?prevSize .
+}
+INSERT {
+	<@iri> knora-admin:projectRestrictedViewSize "@size"^^xsd:string .
+}
+WHERE {
+    <@iri> a knora-admin:knoraProject .
+    OPTIONAL {
+        <@iri> knora-admin:projectRestrictedViewSize ?prevSize .
+    }
+}
diff --git a/webapi/src/test/scala/dsp/valueobjects/RestrictedViewSizeSpec.scala b/webapi/src/test/scala/dsp/valueobjects/RestrictedViewSizeSpec.scala
new file mode 100644
index 0000000000..3a84a27064
--- /dev/null
+++ b/webapi/src/test/scala/dsp/valueobjects/RestrictedViewSizeSpec.scala
@@ -0,0 +1,47 @@
+/*
+ * Copyright © 2021 - 2023 Swiss National Data and Service Center for the Humanities and/or DaSCH Service Platform contributors.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package dsp.valueobjects
+
+import zio.test._
+
+/**
+ * This spec is used to test the [[dsp.valueobjects.RestrictedViewSize]] value object creation.
+ */
+object RestrictedViewSizeSpec extends ZIOSpecDefault {
+
+  def spec = suite("Size")(
+    test("should succeed on passing percentage values") {
+      val gen = Gen.int(1, 100)
+      check(gen) { int =>
+        val param = s"pct:$int"
+        assertTrue(RestrictedViewSize.make(param).map(_.value) == Right(param))
+      }
+    },
+    test("should succeed on passing the same x y dimensions") {
+      val gen = Gen.int(1, 1000)
+      check(gen) { integer =>
+        val param = s"!$integer,$integer"
+        assertTrue(RestrictedViewSize.make(param).map(_.value) == Right(param))
+      }
+    },
+    test("should fail on passing negative x y dimensions") {
+      val gen = Gen.int(-1000, -1)
+      check(gen) { integer =>
+        val param = s"!$integer,$integer"
+        assertTrue(RestrictedViewSize.make(param).map(_.value) == Left(ErrorMessages.RestrictedViewSizeInvalid(param)))
+      }
+    },
+    test("should fail on passing incorrect values") {
+      val gen = Gen.fromIterable(Seq("!512,100", "pct:-1", "pct:0", "pct:101"))
+      check(gen) { param =>
+        assertTrue(RestrictedViewSize.make(param) == Left(ErrorMessages.RestrictedViewSizeInvalid(param)))
+      }
+    },
+    test("should fail on passing empty value") {
+      assertTrue(RestrictedViewSize.make("") == Left(ErrorMessages.RestrictedViewSizeMissing))
+    }
+  )
+}
diff --git a/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectADMRestServiceMock.scala b/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectADMRestServiceMock.scala
index 6ba1e27760..2a202abc02 100644
--- a/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectADMRestServiceMock.scala
+++ b/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectADMRestServiceMock.scala
@@ -10,6 +10,7 @@ import zio._
 import zio.mock._
 
 import dsp.valueobjects.Iri._
+import dsp.valueobjects.RestrictedViewSize
 import org.knora.webapi.messages.admin.responder.projectsmessages._
 import org.knora.webapi.messages.admin.responder.usersmessages.UserADM
 import org.knora.webapi.slice.admin.api.model.ProjectDataGetResponseADM
@@ -97,6 +98,12 @@ object ProjectADMRestServiceMock extends Mock[ProjectADMRestService] {
         override def importProject(projectIri: IRI, requestingUser: UserADM): Task[ProjectImportResponse] = ???
 
         override def listExports(requestingUser: UserADM): Task[Chunk[ProjectExportInfoResponse]] = ???
+
+        override def setProjectRestrictedViewSettings(
+          id: ProjectIdentifierADM,
+          user: UserADM,
+          size: RestrictedViewSize
+        ): Task[ProjectRestrictedViewSizeResponseADM] = ???
       }
     }
 }
diff --git a/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsResponderADMMock.scala b/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsResponderADMMock.scala
index 818c909a4f..b425279898 100644
--- a/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsResponderADMMock.scala
+++ b/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsResponderADMMock.scala
@@ -16,19 +16,7 @@ import zio.mock.Proxy
 import java.util.UUID
 
 import dsp.valueobjects.Iri
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectAdminMembersGetResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectCreatePayloadADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectGetResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectKeywordsGetResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectMembersGetResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectOperationResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectRestrictedViewSettingsADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectRestrictedViewSettingsGetResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectUpdatePayloadADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectsGetResponseADM
-import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectsKeywordsGetResponseADM
+import org.knora.webapi.messages.admin.responder.projectsmessages._
 import org.knora.webapi.messages.admin.responder.usersmessages.UserADM
 
 object ProjectsResponderADMMock extends Mock[ProjectsResponderADM] {
diff --git a/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsServiceLiveSpec.scala b/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsServiceLiveSpec.scala
index 45a40aa1c3..c2ae32e209 100644
--- a/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsServiceLiveSpec.scala
+++ b/webapi/src/test/scala/org/knora/webapi/responders/admin/ProjectsServiceLiveSpec.scala
@@ -22,6 +22,7 @@ import org.knora.webapi.slice.admin.domain.service.DspIngestClientMock
 import org.knora.webapi.slice.admin.domain.service.ProjectExportServiceStub
 import org.knora.webapi.slice.admin.domain.service.ProjectExportStorageServiceLive
 import org.knora.webapi.slice.admin.domain.service.ProjectImportServiceLive
+import org.knora.webapi.store.triplestore.impl.TriplestoreServiceLive
 
 object ProjectsServiceLiveSpec extends ZIOSpecDefault {
 
@@ -58,6 +59,8 @@ object ProjectsServiceLiveSpec extends ZIOSpecDefault {
 
   private def projectServiceLayer(exp: Expectation[ProjectsResponderADM]): ULayer[ProjectADMRestService] =
     ZLayer.make[ProjectADMRestService](
+      TriplestoreServiceLive.layer,
+      StringFormatter.test,
       ProjectsADMRestServiceLive.layer,
       exp.toLayer,
       org.knora.webapi.slice.common.api.RestPermissionServiceLive.layer,
diff --git a/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/repo/service/KnoraProjectRepoInMemory.scala b/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/repo/service/KnoraProjectRepoInMemory.scala
index e234aefed1..d9a9de8455 100644
--- a/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/repo/service/KnoraProjectRepoInMemory.scala
+++ b/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/repo/service/KnoraProjectRepoInMemory.scala
@@ -10,6 +10,7 @@ import zio.Task
 import zio.ULayer
 import zio.ZLayer
 
+import dsp.valueobjects.RestrictedViewSize
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM
 import org.knora.webapi.slice.admin.domain.model.KnoraProject
 import org.knora.webapi.slice.admin.domain.service.KnoraProjectRepo
@@ -32,6 +33,8 @@ final case class KnoraProjectRepoInMemory(projects: Ref[List[KnoraProject]])
 
   override def findOntologies(project: KnoraProject): Task[List[InternalIri]] =
     throw new UnsupportedOperationException("not implemented (yet)")
+
+  override def setProjectRestrictedViewSize(project: KnoraProject, size: RestrictedViewSize): Task[Unit] = ???
 }
 
 object KnoraProjectRepoInMemory {
diff --git a/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepoInMemory.scala b/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepoInMemory.scala
index 479a6c4abc..8e7e45cfc7 100644
--- a/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepoInMemory.scala
+++ b/webapi/src/test/scala/org/knora/webapi/slice/admin/domain/service/KnoraProjectRepoInMemory.scala
@@ -10,6 +10,7 @@ import zio.Task
 import zio.ULayer
 import zio.ZLayer
 
+import dsp.valueobjects.RestrictedViewSize
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM.IriIdentifier
 import org.knora.webapi.messages.admin.responder.projectsmessages.ProjectIdentifierADM.ShortcodeIdentifier
@@ -32,6 +33,8 @@ final case class KnoraProjectRepoInMemory(projects: Ref[List[KnoraProject]])
 
   override def findOntologies(project: KnoraProject): Task[List[InternalIri]] =
     throw new UnsupportedOperationException("not yet implemented")
+
+  override def setProjectRestrictedViewSize(project: KnoraProject, size: RestrictedViewSize): Task[Unit] = ???
 }
 
 object KnoraProjectRepoInMemory {