I recently bought a 15 inch Macbook Pro touchbar. I created an abstract background image in Photoshop to use as a desktop image. When I set the image as the desktop image, it seems to be downgraded in quality and causes gradient banding to appear. It is a 16 bit image that displays normally without banding when it is opened in other applications such as Preview. The dimensions and resolution of the image match the retina display. I have tried different file formats without any luck. Any thoughts? Thanks in advance for the reply.