If you look at the images from your seat in front of the computer, Mr. Angry is on the left, and Ms.Calm is on the right.

Get up from your seat, and move back 12 feet, and PRESTO!! they switch places!!

It is said this illusion was created by Phillippe G.Schyns and Aude Oliva of the University of Glasgow.

Does this prove that we sometimes may not be seeing what's actually there?

We present hybrid images, a technique that produces static images with two interpretations, which change as a function of viewing distance. Hybrid images are based on the multiscale processing of images by the human visual system and are motivated by masking studies in visual perception. These images can be used to create compelling displays in which the image appears to change as the viewing distance changes. We show that by taking into account perceptual grouping mechanisms it is possible to build compelling hybrid images with stable percepts at each distance. We show examples in which hybrid images are used to create textures that become visible only when seen up-close, to generate facial expressions whose interpretation changes with viewing distance, and to visualize changes over time within a single picture.

http://www.cbim.rutgers.edu/papers/regionFeature_registration.pdf