An image output method includes capturing an image of code pattern including device information specifying an image output device, obtaining the device information from the image of code pattern, obtaining user information specifying a user, and outputting the device information and the user information to an external device, by an information processing device; authenticating the user based on the user information, by a processor; executing image output processing instructed by the user authenticated based on the user information, by the image output device specified based on the device information; transmitting a result of the image output processing by the image output device to the information processing device, by the image output device; and displaying the result of the image output processing by the information processing device.