I've heard those kinds of web sites have very low CTR with Adsense... same as the other thousands of clone sites on Flash games or proxies or discussion boards. You're probably better off finding other source of revenues (such as CPM advertising like DoubleClick) or maybe start another web site on a different topic.
Image hosting website + Adsense = Wrong. That makes sense too, as you would want ads related to the image's content and you're getting ads based on the domain now, probably.
Try affiate systems, try CPM ads if you have MASSIVE amounts of traffic, or try more aggressive systems like Adbrite who allow you to be a #*$! and who also look less like ads... It's against my ethics, but it COULD work ;)