In searching for a desired image from an external storage device which stores
a plurality of images, similarity between a designated search source image and
each of the plurality of images is calculated on the basis of the feature amount
of the designated search source image and the feature amounts of the plurality
of images. A similar image is extracted from the plurality of images on the basis
of the calculated image similarity. In calculating the similarity, an image is
segmented into a plurality of regions, different weights are set for the respective
regions, and the similarity is calculated using the set weights.