A testing method for a camera system having a control unit and at least one camera. The control unit carries out the following method steps immediately after loading of an operating system of the control unit: generating transmittable image data as a function of at least one source image loaded from an electronic camera memory of the camera; transmitting the generated image data from the camera to the control unit; generating an intermediate image as a function of the received image data in the control unit; ascertaining a processed image as a function of the generated intermediate image in the control unit; comparing the processed image to at least one reference image, the reference image being loaded from a memory; and generating an error signal in the event of a deviation between the processed image and the reference image.