I had to deal with 2 separate fake facebook accounts that used photoshopped images of me during HS (>10 years ago). The fake accounts both had way way more friends than me, posted more frequently, were utterly humiliating and embarrassing. Throughout high school I had a bad reputation that proceeded me, it made making friends extremely difficult, and on top of a few other confounding factors made my HS experience so bad I basically gave up. I never found out who was behind the accounts.

I remember at the time this was a pretty common thing, in high schools, so perhaps you just managed to avoid it.