What is a best practice for tagging docker images?

I’m using plugins/docker to build and publish images to my repo. I’m not quite sure what the best practice is for tagging the images automatically. Should there be a new version tag somewhere in source so tht it’s retrieved and applied to build? Should I use something like DRONE_BUILD_NUMBER ?

What’s the recommended way?

we use auto-tagging internally which we view as best practice:

however, autotagging is very opinionated and cannot be customized, which means you may need to come up with your own tagging scheme if you don’t like ours. Some people use build number to create a dynamic tag, others use commit sha, etc.