1. An image processing device, comprising: a change-between-images calculating unit that calculates an amount of change between images in time-series images that are made up of a plurality of images sequentially obtained, the amount of change between images indicating an amount of change between each of the time-series images and a close image temporally close to the each of the time-series images; a primary-digest-image-group extracting unit that extracts a group of primary digest images from the time-series images on the basis of the amount of change between images; a change-in-section calculating unit that calculates an amount of change in section with respect to a time-series image section of the time-series images, the time-series section being defined by each image of the group of primary digest images; and a digest-image-group extracting unit that extracts a group of digest images from the time-series images on the basis of both the amount of change between images and the amount of change in section.