Foxi gives some advice on what basic things to install when starting out with a fresh install of Linux Mint and shows some of the built-in features.
GIMP website (download page):
http://www.gimp.org/downloads/
Windows Version of GIMP 2.8 Download link:
http://download.gimp.org/pub/gimp/v2....
EDIT 11/19/14: The ia32-libs package has been completely replaced by lib32z1, lib32ncurses5, and lib32bz2-1.0 Get these through your software manager and you will be set :3