Paint.NET is free image and photo editing software for computers that run Windows. It features an intuitive and innovative user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools. An active and growing online community provides friendly help, tutorials, and plugins.
This has probably been posted before, but I have just found it today and it seems pretty good. I'm guessing it's something similar to photoshop but a free version.