docker save 
docker load

docker save  将镜像保存成 tar 文件
docker save -o busybox.tar busybox

docker load  导入镜像 
docker load < busybox.tar 
docker load --input busybox.tar


docker images
REPOSITORY                    TAG       IMAGE ID       CREATED        SIZE
busybox                       latest    3c19bafed223   5 weeks ago    1.41MB

docker save -o busybox.tar busybox

docker rmi busybox
Error response from daemon: conflict: unable to remove repository reference "busybox" (must force) - container 78d3e2b79f7f is using its referenced image 3c19bafed223

docker rmi -f busybox
Untagged: busybox:latest
Untagged: busybox@sha256:3614ca5eacf0a3a1bcc361c939202a974b4902b9334ff36eb29ffe9011aaad83
Deleted: sha256:3c19bafed22355e11a608c4b613d87d06b9cdd37d378e6e0176cbc8e7144d5c6

docker load -i busybox.tar