First, most of these people reposting "Share if you believe in Jesus!" images, etc., are so scared of their "afterlife" that they truly believe what they are posting makes a difference. As if their deity had the foresight to see Facebook as a vehicle for spreading his good news, and is reading every page to make sure his believers are doing their duty.
Second, these people are so desperate to please their make-believe god that they don't even realize most of these images and sites are scams to gain more "friends" or "followers," so it's sad and quite annoying. I've had to unfollow quite a few family members because it just got to be too much to weed through to see what was actually important in my news feed, etc.
But I am seeing another side to this coin that is bothering me as well. There are a few atheistic pages/people I follow on FB, and lately their memes, while comical and entertaining some of the time, are quite often childish, unprovoked and downright disgusting. I see that these people are trying to create some sort of cyber balancing act, putting atheist memes out to counteract the theist memes, and I get that. It's like politicians getting equal air time on networks during an election year.
It's the immaturity of these memes that gets me. Atheists are often looked at as strident, arrogant, insulting and militant, which I find unfair and mostly ignorant. But when images of Jesus performing sex acts or whatever are posted for no reason other than shock value, it only makes atheists look bad.
There's nothing wrong with presenting facts, refuting ridiculous claims and even using ridicule when confronted with irrational theists, but unprovoked salvos of horrific anti-religious imagery is really uncalled for and sad.