I replaced 200, 200 with Screen.width and Screen.height, the image quality is much better. webcamTexture = new WebCamTexture(WebCamTexture.devices[0].name, Screen.width, Screen.height, 60);
To brighten the image:
If you bring the image into a standard texture you can use something like Graphics.DrawTexture(). It’s neutral value for color is (0.5, 0.5, 0.5), so anything above this value should brighten the image. You could also put the texture on a plane in the scene, and then you could any number of shaders that allow “over-brightening.”