In light from above heuristic, they we perceive spheres and indention are altered. Our eyes are so much used to of sunlight, that we assume that the light is coming from above and creating a presumption that light on the bottom creates an indention.
This is why Jimmy perceived bumps originally when he looked the picture of the side of the submarine but later when he turned the picture upside down, what he originally perceived as bumps, now look like dents,
