In an image forming system, after receiving print data, print setting data, and a command to display a preview from an information processing apparatus, an image drawing unit in an image forming apparatus generates a preview image that reflects the print setting data from the print data and send it to the information processing apparatus. After receiving the print data, the print setting data, and the command to start printing from the information processing apparatus, the image drawing unit generates drawing data that reflects the print setting data from the print data, and an engine unit prints out an image on paper.