The image of a human is detected from within the image of a subject and the human whose image has been detected is identified. Pet information concerning the identified human is found from a personal information table indicating the correspondence between humans and the pet information that has been associated with these humans. The image of the pet in the found pet information is found from the image of the subject. Thus, rather than all animals included in the image of the subject being found, the image of the pet associated with the particular human is detected. A pet image is thus detected in comparatively simple fashion.