Oh my god ... This isn't normal creepy.

I read all the comments here and it is so awful that some people try to rationalize the behavior of OP's follower. I use the word follower because there isn't much information of were he got the picture from. To me, there is a difference between taking the pictures himself (even if it was during public events) or just collecting them from public channels. Also I can read between the lines that OP and her follower were in the same school in the past but it is not clear if the really knew/know each other, were the ever friends or even acquaintances? Knowing that, could help to understand the build-up of the actions of the follower. But it doesn't change the fact that his behavior is strange and could lead to potentially dangerous actions. OP has the right be afraid and undertake legal actions against him.

Sounds like a Criminal minds episode.