The processor 301 may detect a remaining region from the one or more third images corresponding to the one or more candidate images, except for an external object identical to an external object included in the candidate images. The processor 301 may generate one or more still images using the external object included in the one or more candidate images and the remaining region detected from the one or more third images. The processor 301 may generate one or more still images based on the one or more third images corresponding to the one or more candidate images.