Looking at it without zooming in i got the impression that her hands were looking darker because they were being shadowerd by obama's shoulders. There does seem to be something funky upon closer inspection, but as someone else said its a shitty quality polaroid picture that someone probably messed with to improve picture quality.
why someone would make the effort of cropping out a black guy and putting his mother in, instead of not posting any pic up at all makes no sense.
I suppose humans are prone to believe what they want to believe..