Daniel Brami on Twitter | Polaroid pictures, Poloroid pictures, Polaroid photos
About: Complete Guide For Binding of Isaac Rebirth (iOS App Store version) | | Apptopia
How to open strange door without polaroid and negative | The Binding of Isaac Repentance guide - YouTube
Steam Workshop::the polaroid (and the negative) but awesome
The 10 Best Trinkets in "The Binding of Isaac: Rebirth" - LevelSkip
Apparently gulping the faded Polaroid makes it unable to open the door in depths which I guess makes sense since you can't put it in the door if you swallowed it :
The Binding of Isaac: Repentance Tainted Characters Guide - GameSkinny
Isaac Reforged - Skymods
New Trinkets - The Binding of Isaac: Rebirth Guide - IGN
The Binding of Isaac Repentance Patch Notes - Full List of New Features