A mug shot (also known as a mugshot, head shot, or 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.
Prior to the advent of computer technology, the accused was asked to hold a card with their name, the date, and other information on it. In recent years, digital photography is used for the booking process, and the accused now is no longer asked to hold the card while the photo is taken. Rather the digital photograph is linked to a database record concerning the arrest.