Photo Booth is a software application for taking photos and videos with an iSight camera by Apple Inc. for Mac OS X and iOS. Photo Booth consists of a single window containing a viewer that provides a preview when taking photo snapshots or video clips. Thumbnails of saved photos and videos are displayed along the bottom of the window. These can be shown or played by double clicking on the thumbnails. Clicking the large red button underneath the preview area starts a 3-second countdown, after which a photo is snapped or a video clip begins recording, depending on which setting is selected. Effects can be applied by clicking on the "Effects" button. In addition, users can apply backdrops to provide an effect similar to a green screen. When a backdrop is selected, a message appears telling the user to step away from the camera. Once the background is analyzed, the user steps back in front of the camera and is shown in front of the chosen backdrop.