You create the docker image on your local computer, create checksum and write it down / remember it. Then you just use this checksum when downloading the image

You create the docker image on your local computer, create checksum and write it down / remember it. Then you just use this checksum when downloading the image from other computers to check it's the same one. This only works for images created and uploaded by you of course, for images created by other people it does not work.