The technique of the present invention ensures flexible image processing that is performed integrally on a plurality of image data.In accordance with the present invention, an image output system enables output of the image data, which is generated in a digital still camera DSC 12, with a color printer 20. The DSC 12 generates an image file, in which the image data, image processing control data and an additional data are stored. The image processing control data, which is preset by the manufacturer, may be specified regarding each image. The additional data is the user-configurable data, which is stored into the DSC. The color printer 20 performs image processing based on the image processing control data and the additional data, which is included in the image file, and outputs the resulting image.