This is such a complex issue but I think it is pretty obvious that law is not the solution to minors being sexualized on the internet. The only solution I see is for parents to keep their children off the internet. 

Young girls do not understand why it is wrong or dangerous, so they will naturally oversexualize themselves because it is what gets them the most interaction on social media. 

Boys also face problems with internet access. When I was 12, I would cast my PS3 to my PSP and look up boobs on YouTube. When I got an iPod touch at 13, it became much easier to watch porn. By age 14 I had seen more shit than a human should. I had seen beheadings, gore, blown up bodies, etc. 

The only solution is for children to have no access to the internet. If they have access, they will get around whatever safeguards you might put in place. Many girls will become addicted to validation, and boys will become addicted to porn. A silly ban isn’t enough to protect them. It is all up to the parents.