Throughout the game there are Polaroid-style instant photos that you collect. These poloroids depict cartoony representations of events in the game and to get them requires you to take an alternate route through the level.
The poloroids have basically been implimented as a way to motivate you to play the game in a different way and make you realise that there will sometimes be an alternate sequence to a puzzle. The poloroids themselves are extras that can be picked up by taking an alternate path through a level. When you collect them you can place them on your wall.
The video below will show you how to get all the poloroids in Framed 2.