7.9. Red-Eye

Let's say you snap a near-perfect family portrait: The focus is sharp, the composition is balanced, everyone's smiling. And then you notice it: Uncle Mitch, standing dead center in the picture, looks like a vampire bat. His eyes are glowing red, as though illuminated by the evil within.

You've been victimized by red eye, a common problem in flash photography. This creepy possessed-by-aliens look has ruined many an otherwise-great photo.