When attribute information cannot be generated from received data, image processing methods and image processing parameters are set unequivocally independently of the received data. If the same image processing methods and image processing parameters are set, processing that does not match the purpose of output or user's favor in terms of image quality may be executed. Hence, if the received data is not PDL data and does not include any interpretable attribute information, a reception print mode is checked. If “character priority” is selected for the reception print mode, attribute flag data of a character attribute is generated. If “photo priority” is selected, attribute flag data of a photo attribute is generated. If “auto” is set, automatic generation of attribute flag data is performed. When attribute flag data cannot be generated, detailed settings are checked to generate attribute flag data of a character attribute or photo attribute.