1. An image processor connected to an image output apparatus, comprising: image processing means for performing predetermined image processing on image data using photographing information when photographing to acquire said image data; preprocessing means for performing preprocessing of said predetermined image processing on said image data; and determination means for determining whether said image output apparatus comprises said image processing means or not, p 1 wherein said determination means determines that said image processor performs said preprocessing and said predetermined image processing, when said image output apparatus does not comprise said image processing means.