There's also something about to be said about reposts, which expand the reach by someone else's control. Many a dunk are performed this way and bring on the mob.

Also image sharing being easy. FB is overrun with (maybe real, maybe false) images of Twitter and Reddit posts and and comments. Images also tend to encourage simplistic statements, strawman attack, out of context quotes, etc.

I would separate actual image sharing from screenshots that are more akin to reposts, the later often being the rage bate variety.