Since an image projected from a projector has basically not high quality due to degradation of brightness and mixture of outside light, the image shot by the conventional technology includes the projected image with basically not high quality. In order to solve the above deficiency, in an aspect of the present invention provides an image system, where live performance is provided to audience by image projection on the screen, and the image to be shot does not include the projected image with low quality. For example, the image system can later synthesize a high-quality image having the same content as the projected image.