The Pic Bubbler app for iPhone transforms photos of swimsuit-clad people into titillating, NSFW-seeming images.
The app, available from iTunes for 99 cents, uses an optical illusion called "bubbling," which strategically covers people's naughty parts (and their clothing), but gives the viewer the impression that the figure is naked.
When you upload a photo of a swimsuit-clad figure, the program applies a transparent layer that you can manipulate using the iPhone's touch screen. You can poke holes--bubbles--in the surface of the transparent layer, opening up patches of skin while keeping clothed areas hidden.