"A free powerful application to edit and retouch photos."
As you can probably work out just from its name, Paint NET is a powerful application to edit and retouch photos. The program was born out of the original idea of Microsoft Paint (which comes with Windows), and from this base they have incorporated new design utilities like layers, undo operations and much more.
Paint NET is a development project with the latest in graphics technology and programming (using Microsoft C# language and GDI+ libraries) to get a tool with innumerable abilities and a high speed. And the most important: it's totally free. 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.
This Paint NET program is very easy to download, install and then use, through its friendly and intuitive user interface. You don't need any technical experience at all to get the most out of it.