The object is to enable a user to efficiently set a function for an image processing apparatus using a display medium he carries. When a user operates his mobile phone to activate a function setting information input program, an input screen for setting a function is displayed. When the user inputs function setting information, the mobile phone performs a code conversion for the function setting information to create a code image, and displays it on a display section. The user holds up the code image displayed on the mobile phone to a reading section of an image processing apparatus. The reading section reads the code image. The image processing apparatus performs authentication of the user, and then, it extracts the function setting information from the code image and sets a function. The image processing apparatus performs image processing in accordance with the function.