Abstract: A so-called open image forming system is disclosed that reduces the burden on the user and the system administrator, and permits anyone to use the system and not just users whose use rights have been defined. The image forming system includes printing devices that form images on paper based upon image information, a plurality of terminal devices that are connected to the printing devices via a network and which can transmit an e-mail containing image information to the network, and a server that sends e-mails in response to receiving an e-mail containing image information and that will transmit a predetermined password that identifies the image information to a data transmission terminal device that is one of the plurality of terminal devices.