diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f3df13a..0c86dc9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,10 +11,14 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go_version: [1.18, 1.19]
+        go_version: [ 1.18, 1.19 ]
     steps:
     - name: Checkout
       uses: actions/checkout@v3
+    - name: Install Dependencies
+      run: |
+        sudo apt update
+        sudo apt install -y webp
     - name: Setup Go
       uses: actions/setup-go@v3
       with:
diff --git a/Dockerfile b/Dockerfile
index e3d98fb..ac17290 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,10 +6,15 @@ WORKDIR /go/src/oyaki
 COPY . /go/src/oyaki
 
 RUN CGO_ENABLED=0 go build -ldflags "-s -w -X main.version=${OYAKI_VERSION}" -o /go/bin/oyaki
+RUN apt update && apt install -y curl \
+ && curl https://storage.googleapis.com/downloads.webmproject.org/releases/webp/libwebp-1.3.1-linux-x86-64.tar.gz --output libwebp.tar.gz \
+ && tar vzxf libwebp.tar.gz \
+ && mv libwebp-1.3.1-linux-x86-64/bin/cwebp /go/bin/
 
 FROM gcr.io/distroless/static-debian11
 
 COPY --from=build /go/bin/oyaki /
+COPY --from=build /go/bin/cwebp /bin/
 
 EXPOSE 8080
 
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..e69de29
diff --git a/main.go b/main.go
index db685a5..b8929ea 100644
--- a/main.go
+++ b/main.go
@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"path/filepath"
 	"runtime/debug"
 	"strconv"
 	"syscall"
@@ -77,12 +78,22 @@ func proxy(w http.ResponseWriter, r *http.Request) {
 	if len(xff) > 1 {
 		req.Header.Set("X-Forwarded-For", xff)
 	}
-
-	orgRes, err := client.Do(req)
-	if err != nil {
-		http.Error(w, "Get origin failed", http.StatusBadGateway)
-		log.Printf("Get origin failed. %v\n", err)
-		return
+	var orgRes *http.Response
+	pathExt := filepath.Ext(req.URL.Path)
+	if pathExt == ".webp" {
+		orgRes, err = doWebp(req)
+		if err != nil {
+			http.Error(w, "Get origin failed", http.StatusBadGateway)
+			log.Printf("Get origin failed. %v\n", err)
+			return
+		}
+	} else {
+		orgRes, err = client.Do(req)
+		if err != nil {
+			http.Error(w, "Get origin failed", http.StatusBadGateway)
+			log.Printf("Get origin failed. %v\n", err)
+			return
+		}
 	}
 	defer orgRes.Body.Close()
 
@@ -130,8 +141,18 @@ func proxy(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	defer buf.Reset()
+	if pathExt == ".webp" {
+		buf, err = convWebp(buf, []string{})
+		if err != nil {
+			http.Error(w, "image convert failed", http.StatusInternalServerError)
+			log.Printf("Read origin body failed. %v\n", err)
+			return
 
-	w.Header().Set("Content-Type", "image/jpeg")
+		}
+		w.Header().Set("Content-Type", "image/webp")
+	} else {
+		w.Header().Set("Content-Type", "image/jpeg")
+	}
 	w.Header().Set("Content-Length", strconv.Itoa(buf.Len()))
 
 	if _, err := io.Copy(w, buf); err != nil {
diff --git a/webp.go b/webp.go
new file mode 100644
index 0000000..9ae0a7c
--- /dev/null
+++ b/webp.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"os/exec"
+)
+
+func doWebp(req *http.Request) (*http.Response, error) {
+	var orgRes *http.Response
+	orgURL := req.URL
+	newPath := orgURL.Path[:len(orgURL.Path)-len(".webp")]
+	newOrgURL, err := url.Parse(fmt.Sprintf("%s://%s%s?%s", orgURL.Scheme, orgURL.Host, newPath, orgURL.RawQuery))
+	if err != nil {
+		log.Println(err)
+		return nil, err
+	}
+	newReq, err := http.NewRequest("GET", newOrgURL.String(), nil)
+	newReq.Header = req.Header
+	if err != nil {
+		log.Println(err)
+		return nil, err
+	}
+	orgRes, err = client.Do(newReq)
+	if err != nil {
+		log.Println(err)
+		return nil, err
+	}
+	if orgRes.StatusCode != 200 {
+		log.Println(orgRes.Status)
+		return nil, err
+	}
+	return orgRes, nil
+}
+
+func convWebp(src io.Reader, params []string) (*bytes.Buffer, error) {
+	f, err := os.CreateTemp("/tmp", "")
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	defer os.Remove(f.Name())
+
+	_, err = io.Copy(f, src)
+	if err != nil {
+		return nil, err
+	}
+	params = append(params, "-quiet", "-mt", "-jpeg_like", f.Name(), "-o", "-")
+	out, err := exec.Command("cwebp", params...).Output()
+	if err != nil {
+		log.Println(err)
+		return nil, err
+	}
+	return bytes.NewBuffer(out), nil
+}
diff --git a/webp_test.go b/webp_test.go
new file mode 100644
index 0000000..c67dd62
--- /dev/null
+++ b/webp_test.go
@@ -0,0 +1,56 @@
+package main
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestProxyWebP(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(proxy))
+
+	origin := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.ServeFile(w, r, "./testdata/oyaki.jpg")
+	}))
+
+	orgSrvURL = origin.URL
+	url := ts.URL + "/oyaki.jpg.webp"
+
+	req, _ := http.NewRequest("GET", url, nil)
+	resp, err := doWebp(req)
+	if err != nil {
+		t.Fatal(err)
+	} else {
+		io.ReadAll(resp.Body)
+		resp.Body.Close()
+	}
+	// match with origin file info
+	if resp.Header.Get("Content-Type") != "image/jpeg" {
+		t.Error("wrong header Content-Type")
+		t.Error(resp.Header)
+	}
+}
+
+func TestConvJPG2WebP(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(proxy))
+
+	origin := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.ServeFile(w, r, "./testdata/oyaki.jpg")
+	}))
+
+	orgSrvURL = origin.URL
+	url := ts.URL + "/oyaki.jpg.webp"
+
+	req, _ := http.NewRequest("GET", url, nil)
+	resp, err := doWebp(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	_, err = convWebp(resp.Body, []string{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+}