1. An image forming apparatus comprising: a receiving unit that receives print data including a first bitmap image including a first image area with a first blank space for a first page and a second bitmap image including a second image area with a second blank space for a second page, both of the first and the second image areas being divided from a single image on a display; and a control unit that: extracts the first image area without the first blank space from the first bitmap image and the second image area without the second blank space from the second bitmap image; judges if either the widths of the first and the second image areas or the heights of the first and the second image areas are the same; combines the first and the second image areas to be adjacent up and down if the widths are judged to be the same; and combines the first and the second image areas to be adjacent left and right if the heights are judged to be the same, without changing an aspect ratio of the first image area and an aspect ratio of the second image area.