Photoshop is the world leader in image editing. This is the 'lite' version. This online image editor has all the basic functions that you need. Keeps things simple but produces great results.
http://ictmagic.wikispaces.com/Photos+%26+Images
"When Photoshop, GIMP or similar image editing programs aren't an option, there are more than a few online alternatives that will help make simple changes to your photos and images. No wacky morphing tools here; just the features journalists need."
List of the best Paint.net tutorial.
Paint.NET is free image and photo editing software for computers that run Windows. It features an intuitive and innovative user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools. An active and growing online community provides friendly help, tutorials, and plugins.
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 Microsoft Paint software that comes with Windows, it has grown into a powerful yet simple image and photo editor tool. It has been compared to other digital photo editing software packages such as Adobe® Photoshop®, Corel® Paint Shop Pro®, Microsoft Photo Editor, and The GIMP.