The app, which I assume has a large selection of wallpapers for your iPhone and iPod touch, chose only one screenshot to represent its product -- and that screenshot contains 8 pictures of girls in their underwear, striking various poses, looking at the camera. The app's maker, FunMobility, clearly isn't planning to sell this app based on merit.
Some would argue there's a tasteful way of doing these pictures, but Wallpaper Universe takes the opposite approach. It's actually somewhat surprising Apple let this screenshot slide by the notoriously stringent and presumably prudish App Store approval process.
My favorite part is that one of the pictures has the caption: "i lick this one of me." Another is labeled "Juicey" (yes, misspelled). Yet another is "innocent" (naturally). "Dirty" is the word that comes to my mind.
But what's even dirtier is the price: $5.99. This is certainly one way to get people to pay more for iPhone apps. But considering there are plenty of other wallpaper apps out there, and some of them are free, why would anyone pay $5.99 for this? I'll tell you why. You're looking at it.
For those titillated, find the app here.