docker rmi報錯Error response from daemon

docker commit了一個鏡像之後想删除舊的鏡像，出現以下報錯

Error response from daemon: conflict: unable to delete 6f8214d56bfc (cannot be forced) - image has dependent child images

解決思路：

docker save儲存容器

docker images

docker save REPOSITORY > XX.tar

删除鏡像容器

docker ps -a

docker rm CONTAINER ID

docker rmi IMAGE ID

最後再導入回去

docker load < XX.tar