So about likes or view counts: From my own behavior and from what i have seen on other sites, i'm pretty sure most people don't bother to "like" a post they actually like. For me it's pretty random, usually i don't bother to click the button, then very rarely i do and there will be tons of posts i didn't "like" that i actually liked far more. View counts are more honest in that regard, especially if they count the people who actually downloaded the picture, it just wouldn't work with text posts. And of course it's easy to manipulate a like count without registering. It's still easy to manipulate view counts in absolute numbers, but i expect the absolute numbers on that to be much higher - on other sites there are usually up to 100 views for every "like". I think view counts would overall be more motivating for artists than like buttons, likes could instead be pretty demotivating when nobody bothers to "like" something.

The best idea would probably be a view count for every thread for every time someone clicked on the thread and then a seperate view count for every picture for every time that picture was downloaded.