Gimp is great if you cannot afford on do not want to pay a lot of money for professional software (i.e. Photoshop). According to some it *is* a professional level software, according to other not yet; however it has more than enough features for amateur photo manipulation and other image related tasks (e.g. icon editing, image conversion, resizing etc). The first version was realeased in 1996 by two computer science students (Kimball and Mattis, currently Google engineers).
It is quite complicated to use and probably extreme complicated to master, however it is intuitive enough for simple tasks. Since version 2.6 they invested in an effort to make the interface easier to use (see Wikipedia article). An user manual and documentation page is also available.
set lang=enThen I changed the startmenu entry to point to the bat file instead of the exe file (other settings: execute minimized, use icon of the .exe file).
start gimp-2.6.exe
Name: Gimp
Homepage: http://www.gimp.org/
Version: 2.6.7 (August 14, 2009)
License: free, open-source software
Platform: cross-platform