Image reading device, when connected directly with a printer supporting a predetermined communications standard, enables the printer to print an image with a size or a layout desired by a user, irrespective of the internal setting of the printer. The inventive devices comprises an image detecting portion reading an original image, an image data generating portion generating an original image data, an image data outputting portion which outputs an image data with a communication mode which can be received by a printer supporting a predetermined communication standard and which renders an image represented by the image data printable with the printer, and an image modification processing portion modifying the original image data based on an image data for modification obtained by reading a reference image containing a predetermined pattern printed through the printer, and thereby an original image will printed with a desired size or a desired layout.