imappropriate use of digital email

I know of a girl who had a "friend" take pictures of her in her home without her knowing and then shared them with several students which of course spread like wildfire! I only know about this because then the mother posted on Facebook that this happened and the mother then took the girl out of the school and is now home schooling her. I feel like parents can go a long ways in helping prevent this by early on when their kids start to use phones, which many times they allow way to young in my opinion, steer their kids to friendships that would not develop into this kind of horrible nightmare! I may be naive but surely this could've been prevented. It is so easy for parents to see the kind of kids that their own kids are bringing home these days but checking Digital Media sources.