Paint.NET is free image editing and photo manipulation software designed to be used on computers that run Windows. It supports layers, unlimited undo, special effects, and a wide variety of useful and powerful tools.

The 3.0 release introduces a new multi-document interface (MDI), availability in 8 languages, a highly-requested interactive gradient tool, four new effects, a user-definable color palette, lower disk space usage for scratch files, and a generally cleaner and improved user interface.

Paint.NET started development as an undergraduate college senior design project mentored by Microsoft, and is currently being maintained by some of the alumni that originally worked on it. Originally intended as a free replacement for the MS Paint software that comes with Windows, it has grown into a powerful yet simple tool for photo and image editing.

I've been using it for some time now. Photoshop was always cleverer than I was (and had so many options I get scared) - Paint.NET is a perfect fit for what I need day-to-day