diff --git a/.github/workflows/dockerimage.yml b/.github/workflows/dockerimage.yml
index 79d3c11..ea4bc92 100644
--- a/.github/workflows/dockerimage.yml
+++ b/.github/workflows/dockerimage.yml
@@ -53,7 +53,7 @@ jobs:
         if: github.ref == 'refs/heads/main'
         run: |
           # shellcheck disable=SC2086
-          RC="$(\grep ${IMAGE}/Dockerfile -e '^FROM' | \head -n 1 | \sed -e 's/^.*://')"
+          RC="$(\grep ${IMAGE}/Dockerfile -e '^FROM' | \head -n 1 | \sed -e 's/^.*://; s/@.*$//;')"
           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