Updated Criminal Profile:
GF works at theater. Gave BF the phone as a gift. He doesn't know where she got it, but knows better than to ask. They have 2 kids together, but are on again off again, as the constant pictures indicate a newness of the relationship. The amount of pictures indicate its on again off again. I'll bet there are distant time stamps between bunches of photos. He was at the Save A Lot picking up additional food they ran out of at the Mexican restaurant, where he works (he isn't eating at this time of day).
Consider this crime Sherlock'd