Image Size and Resolution
Apple TV displays standard-resolution images on HD TVs and high-resolution images on 4K TVs. Your app should provide images in both formats.
Provide images with a scale factor of @1x and @2x for all your app’s artwork. In a @1x image, one point equals one pixel. In a @2x image, one point equals two pixels. For example, a Top Shelf image that’s 1940pt × 692pt translates to 3880px × 1384px @2x. Append a suffix of “@2x” to your @2x image names, and insert them into @2x fields in the asset catalog of your Xcode project.
Make sure images are clear at a distance. Remember, your app is across the room on a large screen. Scale images large enough to be seen clearly from far away, and ensure that focus and interaction are easy. This is especially important during gameplay.
Test image quality on both HD and 4K TVs. An image that looks great on your computer screen may appear pixelated or stretched when viewed on a large TV screen. Always test your app on actual televisions to confirm that your images look crisp.