1. A parking camera system, the system including: a plurality of cameras equipped with a vehicle; an input unit allowing a driver to select and input a parking mode; an image synthesizer for synthesizing at least one image photographed by at least one of the plurality of cameras; a memory storing a parking guide line of the vehicle and a parking area image and outputting to the image synthesizer the parking guide line or the parking area image according to the selected parking mode; and an estimated travel trajectory generating and overlaying processor for generating an estimated travel trajectory of the vehicle by receiving steering angle information of the vehicle, and synthesizing the estimated travel trajectory of the vehicle with the at least one image synthesized by the image synthesizer, wherein the image synthesizer synthesizes at least one or more of the parking guide line and the parking area image with the at least one images photographed by the at least one of the plurality of cameras.