"And yet he felt the need to take his own pix."
There are certain mindsets that some people have where they want to be with the "in crowd". Some are "collectors" who just want everything they can get, even though they may never use most of it, eg people who who have libraries of millions of MP3s or films/TV shows they;ll never have time to watch or listen to. Then there's those who feel the need to "give back" to the groups they collected from and then get competitive and not only need to "give back" but to become number one in the group.
In the case of sexual gratification, there are some who wank off to fairly innocuous porm/perv stuff but gradually increase the level of perviness until they can no longer wank off to the innocuous stuff they started with. I suppose it's what might be termed an addictive personality.