IMAGE FORMING SYSTEM

PROBLEM TO BE SOLVED: To prevent the image conversion processing of an image photographed by an image forming apparatus out of management, and to prevent the image from being unlimitedly used.SOLUTION: In an image forming system composed of a plurality of image forming apparatuses for photographing a medium to acquire an image and a host device for performing the image conversion of the image acquired by the image forming apparatus in accordance with a conversion classification, an equipment authentication table in which identification information for specifying each image forming apparatus is registered and an equipment-categorized image conversion table in which the conversion classification of the image is registered in association with the identification information are arranged in the host device, and the host device collates the identification information included in the image information to be transmitted from one of the plurality of image forming apparatuses with the identification information of the equipment authentication table to perform authentication, and when a normal authentication result is obtained, collates the identification information with the identification information of the equipment-categorized image conversion table, and performs image conversion on the basis of the image conversion classification associated with the coincident identification information.