A multi-functional copying machine according to the invention has a scanner for reading the image of a document and image information appended to the document and a printer for forming the image on a medium. It compares the image read by the scanner and the image information, determines according to the extent of alteration of the image whether or not reproduction of the image of the document as it is can be permitted and, if permitted, produces a copy from the reproduced image of the document. If reproduction is forbidden of the image of the document as it is, whether or not to permit restoration of the scanner-read image according to the image information is determined and, if permitted, a copy is produced from the restored image. This makes it possible to keep track of any alteration in a copyrighted image by quick processing, prevent altered copyrighted images from circulation, and protect copyrighted images appropriately.