We have been playing with git. There's more coming! For now, this quick prototype (30M) illustrates some ideas about diff, and images files. It will hopefully be improved in the future :)
[difftool "mydifftool"] cmd = composite $LOCAL $REMOTE -compose difference x:
It's a digest of two stackoverflow threads:
Are there revision control systems for images?
How do I view 'git diff' output with visual diff program?
It's all lo-fi.