how to save a docker image as a tar code example
Example: docker create image from tar file
$ docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
$ docker load < busybox.tar.gz
Loaded image: busybox:latest
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest 769b9341d937 7 weeks ago 2.489 MB
$ docker load --input fedora.tar
Loaded image: fedora:rawhide
Loaded image: fedora:20
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest 769b9341d937 7 weeks ago 2.489 MB
fedora rawhide 0d20aec6529d 7 weeks ago 387 MB
fedora 20 58394af37342 7 weeks ago 385.5 MB
fedora heisenbug 58394af37342 7 weeks ago 385.5 MB
fedora latest 58394af37342 7 weeks ago 385.5 MB