This is because whenever you set a JPEG as wallpaper, Windows 10 automatically compresses and reduces the quality of the original image before setting it as the desktop wallpaper. Disable Desktop Wallpaper JPEG Quality Reduction in Windows 10: Whenever you set a JPEG image as desktop wallpaper you might have noticed that the desktop wallpaper isn’t as sharp as the original image, in short, the quality of the image is not same.
