iPhone app got a launcher image to fool the users to think the app starts very quickly. To create this launch image can be create from the Organizer from Xcode. Open Xcode and go to menu Window -> Organizer or the Organizer icon in the topright corner of Xcode.
Remember to connect your iPhone to your mac if you haven’t already. Go to your device iPhone -> Screenshots -> press “New Screenshot.
If the screenshot is correct for your launch image press “Save as Default Image…”. It will automatically save and add it to your project.