diff --git a/.github/workflows/dockerimage.yml b/.github/workflows/dockerimage.yml
index 9d21e20..e0fc1c0 100644
--- a/.github/workflows/dockerimage.yml
+++ b/.github/workflows/dockerimage.yml
@@ -53,12 +53,12 @@ jobs:
         if: github.event_name != 'pull_request'
         run: |
           # shellcheck disable=SC2086
-          RC="$(\grep ${IMAGE}/Dockerfile -e '^FROM' | sed -e 's/^.*://')"
-          if [[ "${RC}" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]] && ! git show-ref --tags --verify --quiet "refs/tags/v${RC}" ; then
-            echo "RELEASE=${RC}" >> "${GITHUB_ENV}"
+          RC="$(\grep ${IMAGE}/Dockerfile -e '^FROM' | \head -n 1 | \sed -e 's/^.*://')"
+          if [[ "${RC}" =~ ^[0-9]+\.[0-9]+\.[0-9]+$ ]] && ! \git show-ref --tags --verify --quiet "refs/tags/v${RC}" ; then
+            \echo "RELEASE=${RC}" >> "${GITHUB_ENV}"
           fi
       - name: Trigger release
-        if: env.RELEASE == true
+        if: ${{ env.RELEASE != '' }}
         uses: actions/create-release@v1
         env:
           GITHUB_TOKEN: ${{ secrets.RELEASE_TOKEN }}