1. A camera system that includes a plurality of cameras including at least a first camera and a second camera, each of the plurality of cameras comprising: an imaging unit; and an image processing unit operable, if configured to operate in a first mode that is for stand-alone operation, to perform encoding processing on an image captured by the imaging unit, the first camera further comprising: an image receiving unit operable to receive images from other cameras among the plurality of cameras; a first execution unit operable, if configured to operate in a second mode that is for cooperation with said other cameras, to cause the image processing unit of the first camera to generate a synthesized image by synthesizing the images received by the image receiving unit and an image captured by the imaging unit of the first camera; and a synthesized image transmission unit operable to transmit the synthesized image to the second camera, and the second camera further comprising: a synthesized image receiving unit operable to receive the synthesized image from the first camera; and a second execution unit operable, if configured to operate in the second mode, to cause the image processing unit of the second camera to perform part or whole of the encoding processing on the synthesized image received by the synthesized image receiving unit.