It is a subject to provide an information processing apparatus which makes it easy to form program parts depending on individual installation of image output apparatuses and which can suppress an increase in code amount of driver software. The apparatus has program modules for processing quantized image information in accordance with characteristics of an image output apparatus by different methods and virtual switches provided in a program. The modules having the unified interface are switched by the virtual switches in accordance with either a mode of using which image output apparatus as a target and a mode of using which function of the image output apparatus when the image is formed. The formed data is handed to the image output apparatus through a spooler prepared for the OS.