First of all, for parents who monitor their children's smartphone use, Snapchat doesn't save pictures and messages sent so you can see them later.
If there are nude photos, this sick breach of privacy would also be considered child pornography, and those who have distributed the photos or are in possession of the photos could face jail-time.
My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier.