1. An image processing device comprising: an image acquisition section that acquires a plurality of photographic images obtained by photographing a same subject at different photography times; a part identification section that identifies a portion where a predetermined part among parts that form the subject in the photographic images appears; a first processing section that applies first matching processing, which matches two images by transforming one or both of the two images, to two of the plurality of photographic images; and a second processing section that applies second matching processing, which matches two images by transforming one or both of the two images and whose application range of the amount of transformation required for matching is different from that of the first matching processing, to the portion identified by the part identification section in the two of the plurality of photographic images.