[donmcronald]

Assuming it’s similar to Nexus, you can combine multiple registries into a group and you configure the Docker daemon to use your local registry as the (only) mirror.

So if you have ithkuil/project on Docker Hub and donmcronald/project on GCR, you could reference them both with those short names and Artifactory or Nexus would deal with fetching them from the correct remotes.

The main downside is that you introduce the potential for namespace collisions. A second downside is that you become dependent on having that local registry aggregating images from multiple registries. Personally I don’t like it.