That is part of the problem though: in any acceptable interpretation of the law, the one in the photo would be the victim, so how could they be charged with also being the abuser? You can't be your own abuser. I, too, am only aware of cases where this has happened because the receiver then shared it with others; however, the person that received it is also a minor of the same age thus also inappropriate to charge them, but would be the more correct choice.
https://www.aclu.org/news/juvenile-justice/minnesota-prosecu...
This is one such case, but hardly unique.