Cleaning up duplicate docker images
When an image tag is bumped, it can happen that another pipeline in the same project runs before the previous one is done generating the image, so it generates another image for the same tag. The later job will clobber the symbolic tag, but the other image will remain referenced by its job number tag.
It would be good to automatically clean up such duplicate images somehow. Maybe the .*@container-ifnot-exists
templates could do it somehow? E.g. check for any images only referenced by job number tags, and remove those.