1. An image recognition apparatus, comprising: a reading unit that reads an image on a paper script to acquire the image data from the paper script; an additional image extraction unit that extracts an additional image added to each predetermined area of an original image from the difference extraction result by taking a difference between an image data of the original image on the paper script and the image data acquired by the reading unit; an association unit that associates the additional image with the predetermined area; and an additional image selection unit that selects one of a plurality of additional images under prescribed decision conditions, when the plurality of additional images are associated with one predetermined area in accordance with an association made by the association unit.