Computer graphics as well as related disciplines often benefit from understanding the human visual system and its input. In this paper, we study statistical regularities of both conventional as well as high dynamic range images, and find that several commonly held wisdoms regarding natural image statistics do not directly apply to high dynamic range data. These results have implications for both the study of human vision, as well as for the design of algorithms in computer graphics and computer vision that rely on such statistical regularities. CR Categories: I.2.10 [Vision and Scene Understanding]: Modeling and Recovery of Physical Attributes— [G.3]: Probability and Statistics—Statistical Computing