An image data processing system comprises: a first storing unit that previously stores an apparatus information corresponding to an image recording apparatus; a determining unit that determines whether or not the apparatus information stored in the first storing unit is in a predetermined range of values; a notifying unit that notifies whether or not a content of the apparatus information is normal based on a result determined by the determining unit; an instruction acquiring unit that acquires an instruction indicating whether or not an image data is converted by using the apparatus information stored in the first storing unit; a converting unit that converts an image data based on the instruction; and an image data supplying unit that supplies the image data to the image recording apparatus corresponding to the apparatus information.