Say Cheese is a multimedia iPhone app developed by Ken Muehring. The app allows users to capture photos by simply saying the word "cheese" while using either the front or back camera. Users can pinch to zoom in the camera view and choose between portrait or landscape mode for their pictures, which are then saved in the device's photo library. Additionally, the app features a Listen button that activates speech recognition to detect the word "cheese" for capturing photos. Users have the option to take multiple pictures, and the listening function will automatically time out after about a minute, with the ability to manually stop it by tapping the "stop" button.