upload image as artifact

.github/workflows/docker-image.yml

@@ -16,4 +16,15 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Build the Docker image
-      run: docker build . --file Dockerfile --tag my-image-name:$(date +%s)
+      run: docker build . --file Dockerfile --tag geant_tut:$(date +%s)
+    - name: Build and export
+      uses: docker/build-push-action@v6
+      with:
+        tags: geant_tut:latest
+        outputs: type=docker,dest=/tmp/myimage.tar
+    - name: Upload artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: geant_tut
+        path: /tmp/myimage.tar
+