1. A digital camera comprising: an image pickup unit for imaging a subject to obtain digital image data; an image storing unit for storing at least said digital image data of a photographed image that is obtained with said image pick up unit; an image display unit for displaying at least an image being presently photographed; a reference image designating unit with which one or more of at least partial areas of an image to be referenced for image compositing are designated as a reference image area; and an image compositing unit which produces a composite image such that a reference image within said reference image area is displayed on said image display unit as superposed on the image being presently photographed.