manit77

When you delete a tag from docker a private registry, it doesn't delete the image file from disk without running garbage collection. 

# docker swarm
docker exec $(docker ps -q -f name=registry_registry-server) registry garbage-collect /etc/docker/registry/config.yml --delete-untagged

# docker local
docker exec <registry_container_name> registry garbage-collect /etc/docker/registry/config.yml --delete-untagged