1. going on a spree of looking for images
2. going insane after having screwed around with databases, for long periods of time, in the attempts to make maps on Geographic Information Systems (GIS)
"He's going gis crazy, must recently joined fark.com"
"She's gone gis crazy working in the Magellan Lab 22 hours straight"
who's got his whole life predetermined and who is usually so sure of himself (usually someone of upper class who is born into a rich family) - arguably from "pretentious" or the French "prêt" meaning "ready".
Yeah he's got his Jaguar and his 90k a year job handed down from his papa. He's only 24. That's just pure pret, man.