1. A computer-implemented method comprising: receiving, by a computing system, a first image from a first camera of a set of one or more cameras; detecting, in the first image, a face of a first person; comparing, by the computing system, the first image to a set of images stored in a local cache of the computing system, wherein the set of images stored in the local cache are images of one or more persons that have been recognized in at least one image captured by the set of one or more cameras during a recent time period, and wherein the computing system is configured to remove from the local cache images of persons not recognized in any image captured by the set of one or more cameras during the recent time period, such that the first image is compared only to images of the one or more persons that have been recognized in at least one image captured by the set of one or more cameras during the recent time period; determining, based on the comparison, whether the face of the first person matches a face of a person depicted by at least one image of the set of images stored in the local cache; and in response to determining that the face of the first person does not match a face of a person depicted by at least one image of the set of images stored in the local cache: selecting, by the computing system and from a plurality of images of the first person captured by the set of one or more cameras, a highest quality image of the first person that includes a highest quality depiction of the face of the first person, the plurality of images including the first image; providing the highest quality image of the first person to a server system that stores data for multiple people, wherein the server system compares the highest quality image of the first person to images from the data for the multiple people to identify the first person, including comparing the highest quality image of the first person to images of persons stored at the server system that were captured prior to the recent time period; and receiving, by the computing system and from the server system based on a result of comparing the highest quality image of the first person to the images of persons stored at the server system that were captured prior to the recent time period, data that identifies the first person.