Think back to the kids' magazines you had when you were growing up -- there was always a page dedicated to brain teasers. The mazes and word scrambles were okay, but what I really liked were the illustrations of everyday objects with the challenge to "find what's missing in this picture." Sometimes the cat would only have one eye. Sometimes a flower wouldn't have a stem. Sometimes a mirror would be without a reflection. On first glance, nothing seemed amiss. But after a careful study, well, I always felt like such a smartypants when I figured out those things.
So, in the spirit of mindbenders past ... find what's missing in THIS picture. (And, no, I didn't resort to Photoshop.)