An original comprises a first page and a second page as disposed face-down on the platen surface of an image-processing device. The platen is scanned to form a platen image. The positions of two diagonally-opposite corners of the original are determined based on a fixed platen reference point. An original image is formed by cropping the platen image based on the positions of the two original corners. The size and position of either one selected page or both pages are determined based on the two original corner positions. When the image of only one selected page is desired, the image of the selected page is formed by cropping the original image based on the size and position of the selected page. When the images of both pages are desired, the images of both pages are formed by cropping the original image based on the sizes and positions of both pages.