A communication system including a communication apparatus that communicates with a destination apparatus, and an image processor that connects to the communication apparatus. The image processor includes a supplying unit that supplies image data to the communication apparatus, and a notifying unit that transmits first additional information to the communication apparatus. The communication apparatus includes a memory that stores second additional information, a information generator that generates third additional information based on the second additional information stored in the memory and the first additional information received from the image processor, and a transmitter that adds the third additional information generated by the information generator to the image data supplied from the image processor and transmits the image data including the third additional information to the destination apparatus.