Upon synthesizing objects, information bits indicating the types of objects are lost. To solve this problem, this invention provides an image processing apparatus having discrimination means for discriminating a type of object to be rendered, determination means for determining the presence/absence of synthesis of the discriminated object, synthesis means for synthesizing an object and information of the type of object in accordance with the determination result, and processing means for appending information indicating the type of synthesized object to a rendering result obtained by rendering the object to be rendered in units of pixels.