An image processing apparatus for processing image data having attribute information for every pixel of the image data, includes a combining unit that combines component image data, which corresponds to each of a plurality of component images, into composite image data that corresponds to a single composite image, and an attribute appending unit that appends identification information, which indicates the component image data to which each pixel belongs, as attribute information of pixels of the composite image data. In addition, a processing unit applies common image processing to pixels having identical values as the identification information based on the attribute information.