At the top-left corner of the image we see a support bracket for the hand rail. The orientation of this bracket only seems to make sense if we are at the bottom of the stairs looking up at the mattress. The shadow cast by the mattress also looks like the light is above and slightly closer to the camera.

If we were at the top looking down, that would imply that the hand rail brackets were sideways instead of being vertical, and that the light was mounted on the wall instead of the ceiling. I have seen stranger things in construction but it would still be strange and unlikely.