1. An information processing apparatus that estimates a photographer of an image, comprising: a first database in which an imaging device is previously associated with an owner of the imaging device among a plurality of persons; a second database in which the persons are previously associated with their respective personal images; a first determining unit to acquire information about the imaging device associated with an image of interest to be served as an object to be estimated as a photographer, to specify the owner associated with the acquired information about the imaging device with reference to the first database to obtain owner information, and to acquire a first value that represents a probability that each of the plurality of persons is a photographer of the image of interest, based on the owner information; a second determining unit to acquire a second value that represents a probability that each of the plurality of persons is a photographer of the image of interest, based on a result of making a comparison between a subject image included in the image of interest and each personal image in the second database; and a third determining unit to acquire a third value that represents a probability that each of the plurality of persons is a photographer of the image of interest.