Paint.NET is image and photo manipulation software designed to be used on computers that run Windows XP or 2000. Paint.NET is jointly developed at Washington State University with additional help from Microsoft, and is meant to be a free replacement for the MS Paint software that comes with all Windows operating systems.

The programming language used to create Paint.NET is C#, with GDI+ extensions.

Paint.NET has many of the powerful features that expensive commercial applications have, including the ability to use layers.

What's New in version 3.35 Beta 2:

• Changed: When using a selection mode other than "replace", it will now draw the selection outline so that you can see both the original and resulting selection areas. Before, it would only draw the resulting selection area outline, which made modes such as Intersect hard to use.
• Changed: The canvas background is now a solid color instead of a gradient. The gradient was causing certain tone misjudgments related to bright versus dark colors.
• Changed: Shortcut key for Sepia is now Ctrl+Shift+E. The shortcut for Posterize is now Ctrl+Shift+P.
• New: When holding Ctrl or Alt for a selection tool, the cursor now has a plus or minus indicator.
• Fixed: The Resize dialog had some rounding errors with the "Maintain aspect ratio" feature, which caused a few discrepancies and even a spurious "out of memory" error.
• Fixed: Some quirks with the Color Wheel control for IndirectUI-based effect plugins.
• Fixed: Several miscellaneous and rare crashes.
• Fixed: The installer would display a bizarre error if a "blank" install folder was attempted.
• Fixed: The installer now only accepts absolute path locations, instead of relative ones. This fixes an ambiguity between where Paint.NET believes it is installing itself to, and the directory that Windows Installer actually uses.

Requires Microsoft .NET Framework 2.0.