Conventionally, when counterfeit judgment processing by using electronic watermark is performed in a printer driver, a printing speed is lowered due to heavy load. To solve the problem, in the printer driver, first, it is judged whether or not image data indicated by input print information is in high quality. If the image data is in high quality, it is judged whether or not the image data represents a particular image. If the image data represents the particular image, predetermined processing is performed on the image data. This minimizes the execution of counterfeit judgment processing and reduces the load.