The first good free image processing program we recommend is PAINT.NET.
The program must be installed by downloading from the website:
PAINT.NET download page - free for businesses

It is a free application for home use and more, because it can be used even in the company. The program has "LGPL license" which means it's free-of-charge in the classic version.
Link to extensive documentation - unfortunately in English.
You can learn a lot how to take the first steps and more from the Polish guide:
Link to documentation...
Free online photo editor in English PIXLR Link to the page...
The program is worth recommending for those who want more GIMP. Free with great possibilities, fully comparable with Photoshop, easy to find on the web.
GIMP download page - free for businesses