1. A method of processing a plurality of still images, comprising the steps of: detecting an object photographed for each of the still images; arranging the object detected by the step of detecting an object with respect to the plurality of still images and detecting an object photographed by the plurality of still images; relating objects having a strong relationship out of the plurality of objects detected by the step of arranging the object; selecting a still image including at least one of the objects detected by the step of relating objects from the plurality of still images; and outputting the still image selected by the step of selecting a still-image.