1. An image forming system including an image processing device for generating print data, and an image forming device which is connected to the image processing device via a network, and which is able to generate vector data from the print data to spool the vector data, wherein the image processing device comprises: an acquiring component configured to acquire a first processing resolution used for executing resolution dependent processing in the image processing device; a first processing component configured to execute resolution dependent processing in accordance with the acquired first processing resolution if the resolution dependent processing is necessary to generate the print data; a component configured to put resolution information about the acquired first processing resolution into the print data; and a transmitting component configured to transmit the print data containing the resolution information to the image forming device, and wherein the image forming device comprises: a receiving component configured to receive the print data transmitted from the transmitting component; a determining component configured to determine a second resolution at a time when the image forming device executes resolution dependent processing by analyzing the resolution information contained in the print data; and a second processing component configured to execute resolution dependent processing in accordance with the determined second resolution if the resolution dependent processing is necessary to generate the vector data.