When I looked at that photo, it just looks to me to be a poorly done panorama shot. And looking at the title of the link, even the author suggests that could be it.
Have any of you here done panorama shots? I'm not talking about using a special panorama camera, but using a standard digital camera and taking several seperate photos as you move the camera side-to-side, then using sofware to piece them together again. I've done many of those.
Unless you use a tripod and are very precise, that type of photo is what you will often get, especially if you hold the camera in your hand. You can get things to line up at the bottom, but not at the top, or at the top but not the bottom. You will see things duplicated like the one light at the top of the tent.
If it were a photoshop of a single photo, you wouldn't get all the obvious duplicated stuff as you see in that photo. Why would they duplicate a light or tree in a Photoshop? That's extra work, makes it look fake, and doesn't make the crowd look larger. It's simply a panorama shot that wasn't done very well and things didn't line up correctly.