It does not necessarily need to be picture of anyone's junk. It does not need even to be a picture. So let's focus on the real issue here. Puritanism or whatever, extortion needs to be impossible.
Many discussions here about freedom of speech and the value of anonymity to this; the freedom to express ideas without worrying it may explode in our faces later.
I think right-leaning people use "cancel culture" to describe the same category of concerns. At lest, I hope that's what they mean by the term.
Business and governments say similar things, saying that if every meeting is recorded, people will be less willing to speak up.
A society where we don't care about people having had dumb opinions in the past would help more… but that creates a game theoretic risk, we need some kind of reputation system to avoid the iterated prisoners' dilemma degenerating into the ordinary prisoners' dilemma.
I don't have any complete answers. But at the same time, don't let the perfect be the enemy of the good, we can certainly make things better.
Also Taylor Swift will probably save us all if she takes on AI nudes and she can help teens by leading by example. That will help to change the dialog shame and stigma.
We also need to help kids with self-acceptance and reduce shame. But yes, instagram and social media need to do more, that has been clear for awhile.