Tag:
https://docs.docker.com/engine/reference/commandline/tag/#parent-command
root@docker-lab:~# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest c30178c5239f 4 days ago 1.11MB
root@docker-lab:~# docker tag busybox:latest jlk0013/demo-example
root@docker-lab:~# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
jlk0013/demo-example latest c30178c5239f 4 days ago 1.11MB
busybox latest c30178c5239f 4 days ago 1.11MB
Push
https://docs.docker.com/engine/reference/commandline/push/