Conventionally, when a correction parameter is determined on the basis of the feature of an image obtained by analyzing image data, and the image is corrected, the processing speed becomes considerably low. In this invention, for an image file stored in an apparatus, reduced image data held in the file is analyzed to determine a correction parameter in printing, and the image is corrected on the basis of the correction parameter, thereby shortening the processing time. When an appropriate correction parameter is determined for an image file stored in the apparatus and added to the file in advance before printing, and the image is corrected on the basis of the correction parameter in printing, the processing time is further shortened.