Average computer user mostly do simple image or photo retouching such as cropping, rotate, resize, adding text, giving simple effects, etc. in this case Adobe Photoshop would be overkill and way too expensive to buy. A free software that I found is Paint.Net, which is surprisingly powerful for everyday image editing.
For a free software, Paint.Net is rich of features such as Layers which you can only find on professional, expensive image editing software. It have tabbed user interface that give you thumbnail for each images or photos that currently opened on Paint.Net. It support unlimited history of actions that you do on the image that you currently edit.
Another interesting feature is Paint.Net’s special effects. You can remove red eye on your photo very easy, add blurs, pencil sketch, sharpen your photo and many more. If it’s not enough, you can go to Paint.Net’s forum and download plugins to add feature to your Paint.Net installation.
You can download and get tutorials on using Paint.Net here: www.getpaint.net
Installing Paint.Net is very easy, see screenshots below: