Hi Clementine,
If he never used to post on social media before and now that you have removed him off of everything he is posting selfies again and regularly, it could be because he is indeed trying to get your attention.
He may be posting these selfies in the hopes that he can get you to message him.
He seems to be the type who enjoys being at the receiving end of attention.
But, he also may have a habit of sabotaging relationships when they have the potential to become something more substantive.
This may be what happened back when the both of you had been out on a few dates and he suddenly became distant.
Once he sabotages it, he misses the attention and comes back for more after a while.
Keeping this in mind, the attention that he is trying to get from you right now in posting all these selfies may be short-lived, if you were to respond to him for a period of time that satisfies his need for attention.