I’m not saying he’s a robot. I’m just saying it’s possible.
Facial expressions in most family photos aren’t usually this consistent- at least in my family anyways. It’s safe to say that most ordinary personal photos contain a variety of smiles that vary with an individual’s mood. Obama, on the other hand, doesn’t seem to have any fluctuation in all 130 of these photos.
That being said, most ordinary people aren’t constantly hounded by photographers every day. So, as strange as it may seem at first, having a “fake” pre-practiced Hollywood smile is probably one of the overlooked traits that all presidents have.
After all, who would want their only photo with Obama to have a frown in it; even if it is genuine?