The players gave police permission to check the pictures on their cell phone; you would think they'd be smart enough not to consent to the search if they had taken a picture without her permission.

While I suspect there was a rape of the girl -- though apparently only by one of the players, at least initially, since she seems to admit consenting to have sex with the first player -- there is always the chance she is framing them, for some reason. At least one possibility is that she initially was ok with the picture but changed her mind.