Probing discs for console games doesn't usually turn up much, but someone found a ton of extra naughty images of Catherine (such as the three above) and an unused file that hints that Atlus once planned a PC version of the game.
The VG-Resource found the content earlier today. Nothing says a PC Catherine is still a plan or will ever happen, but an image of all the control icons in the game's tutorial sequence shows mouse clicks and keyboard presses alongside Xbox 360 and PS3 commands. We can assume it was at least considered at one point.
The VG-Resource also found several unused images, many for the cell phone in the game, over which Catherine sometimes sends you racy pictures. There were other images, including a player select screen, of unknown intent. Given the surreal nature of the game (which I have not even played yet) I can't even begin to speculate what they're about. But the cell phone pics, yeah, you'll probably want to check those out at the link.
Was Catherine to be Released on PC? [The VG-Resource]