1. An image processing apparatus that generates a joined image by joining a plurality of textures based on a plurality of images, the image processing apparatus comprising: a derivation unit that derives a motion between images of the plurality of images; a frame memory in which a joined image frame is set and the plurality of textures that form the joined image are written; and a texture writing unit that writes the plurality of textures into the frame memory based on the motion between the images, wherein the texture writing unit writes a first texture among the plurality of textures into an area that is not in contact with an edge of the joined image frame.