A noted image information extraction section 31 specifies a region of a noted image in an original image, and noted image information containing information relating to position and size of the noted image WMM region within the original image is extracted. Continuing on, mask image formation means 31 forms a mask image by displaying superimposed on the original image, based on noted image information and mask image information registered in a mask image information file. As a result, a mask image comprised of element images selected using element image selection information contained in mask image information is formed at a specified position and specified size in the noted image region of the original image. A composite image having the mask image superimposed on the original image is then formed by composite image formation means 33. As a result, an image that a user has rendered in an original image is simply and appropriately formed, regardless of whether it is a still image or a moving picture.