The picture is someone taking a picture of another phone. I haven't used it in years but it sort of looks like Snapchat. It's possible they did this thinking it's merely an edgy joke and sent it to friends on Snapchat rather than being so bold as to directly post it to media.

Nah, I'm pretty sure they were just going for shock factor, that's it. Kids these age acting out like this are generally just looking for attention.