diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6ec5568..e820d64 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,12 +16,15 @@ jobs:
     - name: Check out code
       uses: actions/checkout@v2
 
-    - name: Build and push RELEASE and LATEST Docker images
+    - name: Inject slug/short variables
+      uses: rlespinasse/github-slug-action@2.0.0
+
+    - name: Build and push master/tag and latest Docker images
       uses: docker/build-push-action@v1.1.0
       if: ${{ github.event_name == 'push' || github.event_name == 'release' }}
       with:
         repository: cnabio/signy-in-toto-verifier
-        tags: ${{ github.ref}}, latest
+        tags: ${{ env.GITHUB_REF_SLUG }}, latest
         dockerfile: in-toto-container.Dockerfile
         username: ${{ secrets.DOCKER_USERNAME }}
         password: ${{ secrets.DOCKER_PASSWORD }}