About
Paint.NET is image and photo manipulation software designed to be used on computers that run Windows 2000, XP, Vista, or Server 2003. It supports layers, unlimited undo, special effects, and a wide variety of useful and powerful tools.
It started development at Washington State University as an undergraduate 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. The programming language used to create Paint.NET is C#, with a small amount of C++ for setup and shell-integration related functionality.

System Requirements
Minimum Hardware

• Windows XP (SP1 or later), Windows 2000 (SP3 or later), Windows Server 2003, or Windows Vista
  
• .NET Framework 1.1
  
• 400 MHz processor (Recommended: 800 MHz or faster)
  
• 128 MB RAM (Recommended: 512 MB or more)
  
• 1024 x 768 screen resolution
  
• 50+ MB hard drive space
  

Paint.NET v3.35 Released
July 7th, 2008

Whats New:
• New: Posterize adjustment
• New: Intersect selection editing mode
• Improved: Dramatically improved selection editing performance for the Add and Subtract modes (and also for Intersect). The performance used to be dependent on image size, and thus was often unusable on images larger than 1024x768 pixels
• New: When holding Ctrl or Alt for a selection tool, the cursor now has a plus or minus indicator
• 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
• Changed: Hotkeys for selection modes are now Left click for Replace, Control+Left click for Add (union), Alt+Left click for Subtract (difference), Ctrl+Left click for Intersect, and Ctrl+Right click for Invert (xor)
• 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 a
• 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
• Fixed: Sometimes pasting would result in a crash when certain types of malfored data were on the clipboard
• Fixed: It was possible to get around some of the protections imposed by the IndirectUI system. This was causing instability with some effect plugins such as "Fern Fractal"

Download: Paint.NET v3.35