"I might be wrong about this but I reckon GIMP is not an
easy-to-use option, especially if you're coming from a Windows
background, which, if we're honest, is where most of us are coming
from. GIMP also isn’t great for serious photography given its
8-bit-per-channel limitation (Photoshop can do 16- and even
32-bit-per-channel colour). It does do a lot of things right but
given it gets such a rap from most people by default, it’s
worth looking to see what else is out there.
"While Adobe still hasn't made up its mind if it's going to
release a Linux version of Photoshop, what else is there around
that’s free, allows you to create or edit images and doesn't
require a post-grad degree in multimedia graphics to use?"