A mug shot (also known as a mugshot, hea shot, or, properly, booking photograph) is a photographic portrait taken after one is arrested. It was invented by Allan Pinkerton, a famous US detective of the 19th Century. Most mug shots are two-part, with one side-view photo, and one front-view. The Pinkerton National Detective Agency first began using these on "Wanted" posters from the "Wild West" days.