Paint.NET

Paint.NET is a proprietary freeware raster graphics editor program for Microsoft Windows, developed on the .NET Framework. Paint.NET was originally created by Rick Brewster as a Washington State University student project, and has evolved from a simple replacement for the Microsoft Paint program into a powerful editor with support for layers, blending, transparency, and plugins.

Read more about Paint.NET:  Overview, History, Plugins, Support For Non-Windows Operating Systems