In a printer, the image-forming unit performs an image-forming operation in one of a non-saving mode and a saving mode. An amount of the printing agent used in the saving mode is less than an amount of the printing agent used in the non-saving mode. The determining unit determines, based on the remaining amount of the printing agent in the accommodating unit and the remaining times the image-forming unit can perform the image-forming operation, whether the image-forming unit should perform the image-forming operation in the non-saving mode or the saving mode. The controlling unit controls the image-forming unit to perform the image-forming operation in the mode determined by the determining unit.