Location of Image Files
The contents of the /var/lib/docker directory vary depending on the driver Docker is using for storage. By default this will be aufs but can fall back to overlay, overlay2, btrfs, devicemapper or zfs depending on your kernel support. In most places this will be aufs but the RedHats went with devicemapper.
All prepended by "sudo docker":
- rmi (or rmi -f if simple image delete fails)
- ps -a