[freijus]

I also always wondered if there was some version control system for pictures.

[digitalengineer]

There are a few, one by adobe that comes free with the Creative Suite. Some are integrated in Photoshop with a clever UI: http://sixrevisions.com/project-management/the-ultimate-guid...

[icebraining]

Github supports some basic features: https://github.com/blog/817-behold-image-view-modes