An image processing device configured to add, to a first image, a second image, includes an image acquiring unit configured to acquire the second image to be added, a segment sectioning unit configured to section, into a plurality of segments, an image forming area in which the first image is allowed to be formed on a sheet, a segment specifying unit configured to specify, from the plurality of segments, at least one segment into which the second image acquired is to be added, a size determining unit configured to determine a size of the second image such that the second image fits within the at least one segment specified, and an image combining unit configured to create a combined image by adding the second image of the determined size to be formed in the at least one segment to the first image to be formed in the image forming area.