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. It 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. The programming language used to create Paint.NET is C#, with a small amount of C++ for installation and shell-integration related functionality.

Paint.NET can be used to enhance and clean up your photographs. Using the Clone Stamp tool, the power lines that criss-crossed in front of the Space Needle were carefully removed. Other operations were performed that had the effect of smoothing out the image without blurring it, adding some "bloom" (glow), and increasing the contrast.

Features:
Simple, intuitive, and innovative user interface
Every feature and user interface element was designed to be immediately intuitive and quickly learnable without assistance. In order to handle multiple images easily, Paint.NET uses a tabbed document interface. The tabs display a live thumbnail of the image instead of a text description. This makes navigation very simple and fast.

Layers
Usually only found on expensive or complicated professional software, layers form the basis for a rich image composition experience. You may think of them as a stack of transparency slides that, when viewed together at the same time, form one image.

Active Online Community
Paint.NET has an online forum with a friendly, passionate, and ever-expanding community. Be sure to check out the constantly growing list of tutorials and plugins!

Frequently Updated
Updates usually come about every 4 to 8 weeks, and contain new features, performance improvements, and bug fixes. Upgrading to the latest version is very simple, requiring only two clicks of the mouse.