A CPU selects multiple objective image data to be pasted on ornamental image data, analyzes the selected multiple objective image data, and rates the image qualities of the respective image data. The CPU specifies the number of plural layout locations included in the ornamental image data and the priority order of the plural layout locations, and allocates the multiple objective image data to the plural layout locations in the ornamental image data, based on the specified priority order and the ratings of the multiple objective image data. The CPU executes image quality adjustment with regard to the multiple objective image data allocated to the plural layout locations and pastes the quality-adjusted image data on the ornamental image data according to layout control information, so as to generate resulting output image data.