1. An image editing device, comprising: an image data acquisition section for acquiring a plurality of pieces of image data; a reference time interval determination section for determining a new reference time interval; a temporary assignment section for determining, based on respective photographed times of the plurality of pieces of image data and the new reference time interval, a temporary assignment of the plurality of pieces of image data to each of a plurality of pages constituting a compilation so that an interval between photographed times of pieces of image data to be assigned to the each of the plurality of pages is the new reference time interval or smaller; an assignment condition determining section for determining, when the temporary assignment satisfies at least one of a condition for a maximum number of pieces of image data to be assigned to the each of the plurality of pages and a condition for a number of pages of the plurality of pages, the temporary assignment of the plurality of pieces of image data to the each of the plurality of pages that is performed by the temporary assignment section as an assignment of the plurality of pieces of image data to the each of the plurality of pages; and a page image output section for outputting image output data on the each of the plurality of pages based on the assignment.