"GIMP Is No Lame Photo Tool," says this headline from ECT, which insists that "its tool set has all the bells and whistles I used in the Adobe product." If it's really that powerful (which it is, based on my decade of using it), then how come Canonical removes it and keeps F-Spot (Mono) in Ubuntu by default [1, 2]? Here is what the article says:
GIMP is one of the most able-bodied open source photo manipulation apps in the world, and its feature set rivals those of many proprietary -- and often downright expensive -- offerings. Its features will fix flaws in photos as well as enable the user to artistically manipulate images in a multitude of formats. However, most photo editors this advanced do require a bit of a learning curve, and GIMP is no exception.
The Linux world is filled with numerous capable packages for just about every computing category. Graphics manipulation applications are no exception. In any list of able-bodied graphics candidates, GIMP 2.6 should be one of the top three contenders.
[...]
When I left Microsoft (Nasdaq: MSFT) Windows for the Linux platform, I desperately needed an inexpensive replacement for Photoshop. One of the first photo editing apps I encountered was GIMP. It is available in most Linux package management systems. Its tool set has all the bells and whistles I used in the Adobe product.
GIMP became my de facto benchmark measurement for similar photoshopping apps. The fact that GIMP runs on both of my Linux workhorse distros -- Ubuntu and Puppy Linux -- made using it a real bargain.