Portable Gimp.app is the binary distribution of the GNU Image Manipulation Program for Mac OS X packaged as portable application so you can take your preferences with you.
Portable Gimp.app is the Gimp.app the self contained application bundle of the GNU Image Manipulation Program for OS X by Aaron Voisine packaged as portable application so you can carry around with you on any portable device, USB thumb drive, iPod, portable hard drive,memory card, other portable device (also on your internal hard disk) as long as it has 165 MB of free space and use on any Mac OS X computer, taking your preferences with you.
Gimp.app requires Apple's X11 which is included in the "Optional Installs" package on the OS X install disk.