Rumors and fake leaks seem to pop up on a weekly basis. The latest trend among the rumormongers is to take pictures of their so-called leaks with a cellphone and run it through Instagram to give it more credibility. It sure looks a lot more real when you can't pore over the pixels to see just how good or bad their photoshop skills are.
Reddit user rpdj made an interesting post on /r/wow demonstrating how in a few simple steps he created the above image of a new playable race, the Terrorguard. Looks pretty convincing, doesn't it?
Sometimes we see something we like, and because we want it to be true we might give it a little more credibility than it deserves. It's fun to speculate, and maybe these images are just part of the whole process. There's nothing wrong with having a little fun, but just remember that in all likelihood what you're seeing is simply a fan creation.