Several posters have professed doubt about this image. It was not, to the best of our knowledge, produced in photoshop or edited in any misleading way.
The hack in question is achieved, generally speaking, by using a modchip to allow users to connect to their Xbox's hard drives using an ordinary Windows PC, edit the cached map files that Halo 2 (like Halo 1 before it) keeps on the Xbox's hard drive, and then running the game with those edited map caches.