diff --git a/.github/workflows/openscad_build.yml b/.github/workflows/openscad_build.yml
index 498ee86..e8a01d2 100644
--- a/.github/workflows/openscad_build.yml
+++ b/.github/workflows/openscad_build.yml
@@ -1,4 +1,4 @@
-name: Generate and Deploy OpenSCAD preview to GitHub Pages
+name: Generate STL and WebP Thumbnails using OpenSCAD
 
 on:
   push:
@@ -13,21 +13,35 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v2
 
-      - name: Install OpenSCAD
-        run: sudo apt-get install -y openscad
+      - name: Install OpenSCAD and WebP tools
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y openscad webp
 
-      - name: Generate STL files
+      - name: Generate STL files and PNG thumbnails
         run: |
           find . -name "*.scad" | grep -v "^./lib/" | while read scad; do
               stl_path="${scad%.scad}.stl"
+              png_path="${scad%.scad}.png"
               openscad -o $stl_path $scad
+              openscad --render --imgsize=256,256 -o $png_path $scad
+          done
+
+      - name: Convert PNG thumbnails to WebP
+        run: |
+          for png in $(find . -name "*.png"); do
+              cwebp $png -o ${png%.png}.webp
           done
 
+      - name: Clean up directory (Only keep STL and WebP files)
+        run: |
+          find . -type f ! -name "*.stl" ! -name "*.webp" -delete
+
       - name: Deploy to GitHub Pages
         run: |
           git config user.name "GitHub Actions Bot"
           git config user.email "<email>@users.noreply.github.com"
           git checkout -b gh-pages
-          git add ./*.stl **/*.stl
-          git commit -m "Update STL files generated by GitHub Actions"
+          git add ./*.stl **/*.stl ./*.webp **/*.webp
+          git commit -m "Update STL files and WebP thumbnails generated by GitHub Actions"
           git push -f origin gh-pages
diff --git a/chocv1_08u/test1.scad b/chocv1_08u/test1.scad
index 8b3416a..b610ae9 100644
--- a/chocv1_08u/test1.scad
+++ b/chocv1_08u/test1.scad
@@ -1,4 +1,5 @@
 // https://qiita.com/zk_phi/items/ab99315ebaef66e84aa0
+// https://bebebe.hatenablog.jp/entry/2019/06/04/232501
 
 $fs = 0.1;