When the Polaroid photo is shown of Betty and Walter with his boss and his wife, Betty's hands are behind Walter and the boss's wife's back. When it was taken, her left arm was out and her hand was on her own leg.
The amount of snow on Betty's head after Henry Bumps into her varies from shot to shot.
Henry tells Betty that he'd never seen snow before moving to New York because he'd grown up "in the desert" - Tucson, Arizona. While snow in Tucson is considered a "rare" occurrence if Henry had lived there over the past 20 years he would have seen snow at least a dozen times.