A data transmitting device transmits a print file showing file names of image files and print conditions to a data receiving device, and the data receiving device stores the received print file in a storage medium. Then, the data receiving device requests one of the image files from the data transmitting according to the file names shown in the print file, and the data transmitting device transmits the one of the image files to the data receiving device in response to the request. The data receiving device stores the one of the image files in a storage medium and prints the image in the print condition shown in the print file, and the data receiving device and the data transmitting device repeat the steps for each of the image files.