diff --git a/src/modules/webtoon/update/update.controller.ts b/src/modules/webtoon/update/update.controller.ts
index 78dfcac..87439dc 100644
--- a/src/modules/webtoon/update/update.controller.ts
+++ b/src/modules/webtoon/update/update.controller.ts
@@ -1,4 +1,4 @@
-import {Controller, Post, UseGuards} from "@nestjs/common";
+import {Controller, Logger, Post, UseGuards} from "@nestjs/common";
 import {UpdateService} from "./update.service";
 import {ApiBearerAuth, ApiTags} from "@nestjs/swagger";
 import {AdminGuard} from "../admin/guard/admin.guard";
@@ -8,6 +8,9 @@ import {AdminGuard} from "../admin/guard/admin.guard";
 @ApiTags("Update")
 @UseGuards(AdminGuard)
 export class UpdateController{
+
+    private readonly logger = new Logger(UpdateController.name);
+
     constructor(
         private readonly updateService: UpdateService,
     ){}
@@ -15,6 +18,6 @@ export class UpdateController{
     @Post("webtoons/thumbnails")
     @ApiBearerAuth()
     async updateThumbnails(): Promise<void>{
-        await this.updateService.updateThumbnails();
+        this.updateService.updateThumbnails().then(() => this.logger.log("Thumbnails updated"));
     }
 }
diff --git a/src/modules/webtoon/update/update.service.ts b/src/modules/webtoon/update/update.service.ts
index 78dc48e..f2c6cce 100644
--- a/src/modules/webtoon/update/update.service.ts
+++ b/src/modules/webtoon/update/update.service.ts
@@ -1,4 +1,4 @@
-import {Injectable} from "@nestjs/common";
+import {Injectable, Logger} from "@nestjs/common";
 import {PrismaService} from "../../misc/prisma.service";
 import {WebtoonParserService} from "../webtoon/webtoon-parser.service";
 import CachedWebtoonModel from "../webtoon/models/models/cached-webtoon.model";
@@ -10,6 +10,8 @@ import ImageTypes from "../webtoon/models/enums/image-types";
 @Injectable()
 export class UpdateService{
 
+    private readonly logger = new Logger(UpdateService.name);
+
     constructor(
         private readonly prismaService: PrismaService,
         private readonly webtoonParser: WebtoonParserService,
@@ -20,53 +22,65 @@ export class UpdateService{
     async updateThumbnails(): Promise<void>{
         this.webtoonParser.clearCache();
         await this.webtoonParser.loadCache();
-        const dbWebtoons: any[] = await this.prismaService.webtoons.findMany({
-            select: {
-                id: true,
-                title: true,
-                language: true,
-                thumbnail_id: true
-            }
-        });
-        const thumbnailsToDelete: number[] = dbWebtoons.map(webtoon => webtoon.thumbnail_id);
-        // Save new thumbnails
-        const dbThumbnailType = await this.prismaService.imageTypes.findFirst({
-            where: {
-                name: ImageTypes.WEBTOON_THUMBNAIL
-            },
-            select: {
-                id: true
-            }
-        });
-        for(const webtoon of dbWebtoons){
-            const cachedWebtoon: CachedWebtoonModel = this.webtoonParser.findWebtoon(webtoon.title, webtoon.language);
-            const thumbnail: Buffer = await this.miscService.convertThumbnail(cachedWebtoon.thumbnail);
-            const sum: string = this.webtoonDatabaseService.saveImage(thumbnail);
-            const dbThumbnail = await this.prismaService.images.create({
-                data: {
-                    sum: sum,
-                    type_id: dbThumbnailType.id
-                }
-            });
-            await this.prismaService.webtoons.update({
-                where: {
-                    id: webtoon.id
-                },
-                data: {
-                    thumbnail_id: dbThumbnail.id
+        await this.prismaService.$transaction(async(tx) => {
+            const dbWebtoons: any[] = await tx.webtoons.findMany({
+                select: {
+                    id: true,
+                    title: true,
+                    language: true,
+                    thumbnail_id: true
                 }
             });
-        }
+            const thumbnailsToDelete: number[] = dbWebtoons.map(webtoon => webtoon.thumbnail_id);
 
-        // Delete old thumbnails
-        for(const thumbnailId of thumbnailsToDelete){
-            const deletedImage = await this.prismaService.images.delete({
+            // Save new thumbnails
+            const dbThumbnailType = await tx.imageTypes.findFirst({
                 where: {
-                    id: thumbnailId
+                    name: ImageTypes.WEBTOON_THUMBNAIL
+                },
+                select: {
+                    id: true
                 }
             });
-            this.webtoonDatabaseService.removeImage(deletedImage.sum);
-        }
+            for(const webtoon of dbWebtoons){
+                this.logger.debug(`Updating thumbnail for webtoon ${webtoon.title} (${webtoon.language})`);
+                const cachedWebtoon: CachedWebtoonModel = this.webtoonParser.findWebtoon(webtoon.title, webtoon.language);
+                const thumbnail: Buffer = await this.miscService.convertThumbnail(cachedWebtoon.thumbnail);
+                const sum: string = this.webtoonDatabaseService.saveImage(thumbnail);
+                // Check if thumbnail already exists
+                let dbThumbnail = await tx.images.findFirst({
+                    where: {
+                        sum: sum
+                    }
+                });
+                if(dbThumbnail)
+                    thumbnailsToDelete.splice(thumbnailsToDelete.indexOf(dbThumbnail.id), 1);
+                else
+                    dbThumbnail = await tx.images.create({
+                        data: {
+                            sum: sum,
+                            type_id: dbThumbnailType.id
+                        }
+                    });
+                // Update webtoon thumbnail
+                await tx.webtoons.update({
+                    where: {
+                        id: webtoon.id
+                    },
+                    data: {
+                        thumbnail_id: dbThumbnail.id
+                    }
+                });
+            }
+            // Delete old thumbnails
+            for(const thumbnailId of thumbnailsToDelete){
+                const deletedImage = await tx.images.delete({
+                    where: {
+                        id: thumbnailId
+                    }
+                });
+                this.webtoonDatabaseService.removeImage(deletedImage.sum);
+            }
+        });
     }
-
 }