I'm not a professional artist, I just do it for fun from time to time. But coming from a developer background I was wondering if there was a git like versioning program for art?

Like someone paints a picture and uploads all layers etc to the cloud where other can pick it up and modify it, fork it or create branches?

I know versioning art is an important thing with heavy graphics projects like video game development. Those sometimes have terabytes of data for a repository.

I don't know exactly why you are asking this question, or how many art assets might touch something. Usually with art files the repository can blow up really fast. A lot of companies use something like SVN. GIT is great for code, but you might have to download multi-terabytes of data to get the full repo. With SVN, you can just check out the current version and it might "only" be 50-60 GBs.

Artists generally don't work like programmers do. Where you might have a lot of programmers touch one file, you don't really have a lot of artists modifying the same art file.