Paint.net got started in 2004 as senior project at Washington State University mentored by Microsoft and took on a life of its own as an open source graphics and image editor based on Microsoft’s .NET framework for Windows XP/2000/2003. It’s not Photoshop, but it’s serviceable and free, and has built up a following as it has been continually enhanced. The latest release, 2.5, is now available for download as Rick Brewster explains on his weblog:
This release is a huge improvement over v2.1b and is a highly recommended upgrade. The major goals were to improve performance, expand selection support to be much more useful and powerful, provide support for localization to other languages, and to have an easier way for users to have the latest version (update manager). Other features added include the ability to work with measurements in inches and centimeters, a 3D Rotate/Zoom effect, Sepia adjustment, Radial Blur and Add Noise effects, GIF transparency support, TGA file format support, file format plugin support, and a refined Text tool.
Note that .NET Framework 1.1 is required. A version 2.6 is planned for January that will support the newly released .NET Framework 2.0 and thereby be able to add Windows x64 support.