An image forming apparatus comprises: a display which is capable of displaying a preview image of a document, the document consisting of a plurality of pages including one or more text sections in a text data format and one or more illustration sections in an image data format; an illustration section selector which selects one of the one or more illustration sections on any of the pages in the preview image displayed on the display, according to a user operation; a page selector which specifies one of the plurality of pages as a destination page to which the illustration section selected by the illustration section selector is to be transferred, according to a user operation; a realignment portion which transfers the illustration section selected by the illustration section selector to the destination page selected by the page selector and realigns texts in a text section of the destination page; and a controller which allows the display to display a preview image of the destination page including the texts realigned by the realignment portion.