A mail server has a mail receiving section for receiving an electronic mail including attached image data transmitted from a user through Internet, a print user designation managing section for making a user ID and a password for the corresponding user and transmitting them, and a data accumulating unit for making a user directory for each user ID and storing image data therein. When the user ID and the password are inputted from a touch panel by the user, one or more print terminals download the image data from the data accumulating unit through the Internet in order to print the image data. A usage guide including information related to an installation location of the print terminal is provided to the user in a web site (usage guide site).