docker commit了一个镜像之后想删除旧的镜像，出现以下报错

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

解决思路：

docker save保存容器

docker images

docker save REPOSITORY > XX.tar

删除镜像容器

docker ps -a

docker rm CONTAINER ID

docker images

docker rmi IMAGE ID

最后再导入回去

docker load < XX.tar