This is the real image. It was pointed out in class that you can kind of cheat to tell since in the upper right corner, you can actually see the exterior of the box. Interestingly, we can see some artifacts from the camera. In particular, looking at the front-top edges of the two boxes, there seems to be a slight indigo color. For the taller box there's also an extra bit of light coming off that top edge, which is not present in the rendered image. Prof. Hanrahan mentioned that often when people look too carefully at images, they actually begin to think that the real images are the fake ones because they'll notice details that they hadn't noticed before.