1. An image forming method comprising: acquiring a plurality of original images, using a processor, with each of the plurality of original images including a high-resolution area and a low-resolution area, image data for each of the plurality of original images having pixel values corresponding to the high-resolution area and pixel values corresponding to the low-resolution area; detecting, using the processor, a difference between the pixel values corresponding to the high-resolution area of each of the plurality of original images by comparing the pixel values corresponding to respective high-resolution areas of the plurality of original images; adjusting, using the processor, position information associated with the plurality of original images, respectively, based on the detected difference between the pixel values corresponding to the high-resolution area of each of the plurality of original images; and combining, using the processor, the pixel values corresponding to respective low-resolution areas of the plurality of original images in which the position information associated with the plurality of original images is adjusted.