No joke, I was in the middle of creating an example for another problem I was having when I stumbled onto some weird behavior. Can someone explain why this is doing this? It's in cycles by the way.
I applied this to a plane (which was UV unwrapped).
I then went to the blackground tab, clicked on use nodes, and turned the brightness up (1, 1, 1 on RGB) When I rendered it everything was white, I couldn't see the boundaries of the plane. When I turned the color down (so now it's some shade of grey) the plane simply changed color. That little circle is roughly where the plane is (plane is a bit bigger in reality), and, even though you can't see it, the background is also in view. The arrow is pointing to the grey background picture. My texture background is solid white, but now it's grey.