An image processing apparatus of the present invention includes: a blank document determination section determining whether or not input image data is image data of a blank document, regardless of a process mode set for setting a process with respect to the input image data; a storage device storing the input image data in association with a determination result made by the blank document determination section; and a control section (i) reading out the input image data from the storage device and (ii) excluding the input image data determined as image data of a blank document by the blank document determination section, from images to be displayed by the image display device, when the image display device carries out a preview display of the input image data. This configuration makes it possible to carry out a preview display in which a blank document (blank page document) is skipped, without reading the document again.