Launch images are shown during the launch animation when a user launches your app from the home screen, or switches back to it from a backgrounded state.
iOS launch images
We use a "launch storyboard" for iOS to configure your app's launch images. This is to simplify launch image support across a wide range of device sizes and resolutions, and is also required by iOS to support the larger iPad devices at native resolutions.
When you configure your app via our website, you may auto-generate your launch storyboard from one of the other images you've already uploaded such as the app icon, or upload a new image that you'd like to use.