The ability to magically look good in every photo taken of you.
Even the prettiest girls take wonky photos from time to time. If you're caught off guard and aren't doing that thing that makes your double chin disappear and not crossing your eyes and smiling right, you look super weird and then it goes on facebook and you either have to live with it or untag yourself like an asshole.
But! If every time a picture was taken, your big nose and misshaped eye looked amazing, how convenient would that be?