You can elect not to worry about this, as it has no bearing on what will happen when you submit your app to the App Store. However, if you are going to be distributing the test build to beta testers and you want it to show the right icon for them, see the answers posted here:
Basically, you supply a PNG file called "iTunesArtwork" with the desired image, and add it to your xCode project (where it will get copied into your app bundle.)
Oh ok, thanks for that. So when I submit it to the app store the icon that shows up in iTunes to customers will be the correct one?
Yes.To be specific, the game's icon is the one you are already seeing on your test device. The larger version shown in the store is submitted when you set up your app's profile in iTunes Connect (which you can and should do well in advance of your actual file submission.)
Oh ok, thanks for that. So when I submit it to the app store the icon that shows up in iTunes to customers will be the correct one?
– Jason-HYes.To be specific, the game's icon is the one you are already seeing on your test device. The larger version shown in the store is submitted when you set up your app's profile in iTunes Connect (which you can and should do well in advance of your actual file submission.)
– Bampf