It’s gonna turn into a scrum over just how young we’re talking about here. Generally both sides produce anatomy and endocrinology experts who will try and determine the ages of the girls from photographs. And, of course, the prosecution and defense experts will disagree.
All it takes is for one of the minors that looks remotely like one of the ones in the photo to step up and say “Yes that is me.”
If someone does, and a calculation made that shows they were minors at the time ... slam dunk case. Juries have little tolerance for legal shenanigans that try to obscure what they see.