1. A method performed by data processing apparatus, the method comprising: detecting one or more faces based on image data from a camera of a mobile device; determining that one or more of the detected faces correspond to one or more people in a set of people that are classified as being important to a user; in response to determining that one or more of the detected faces correspond to one or more people in the set of people that are classified as being important to the user, determining quality scores for the one or more detected faces that are determined to correspond to one or more people that are classified as important to the user; capturing multiple images with the camera based on the quality scores such that, for each face determined to correspond to a person that is classified as important to the user, at least one of the multiple images includes an image of the face having at least a minimum quality score; and generating a composite image that combines the multiple images.