I have switched to podman for rootless operation, given recent security auditing stuff, and I notice that podman prompts you to choose where to get images from:

[2/3] STEP 1/1: FROM redis:6-bullseye AS redis_base
? Please select an image: 
  ▸ docker.io/library/redis:6-bullseye
    quay.io/redis:6-bullseye

It seems like we ought to just use the fully-qualified image names anyway, as far as I know that is considered good practice given that people can have different registries configured as default?