1. An image processing apparatus for processing at least two still images that are picked up in such a manner that two still images successively picked up have shared portions, the apparatus comprising: a synthesis unit which generates a synthesized image from the at least two still images by synthesizing the shared portions; a capturing unit which captures a plurality of frame images from a plurality of areas in the synthesized image so that a frame image is captured from an area straddling two adjacent still images across the shared portions; and a generation unit which generates a moving image in which the synthesized image is scrolled and displayed, from the plurality of frame images captured by the capturing unit.