As the day approaches when you’re thinking of submitting your app to the App Store, don’t let the prospect of huge fame or big profits hasten you past the all-important final stages of app preparation. Apple has a lot of requirements for your app, such as icons and launch images, and failure to meet them can cause your app to be rejected. Take your time. Make a checklist and go through it carefully. See the iOS Application Programming Guide for full details.
Xcode 4 makes it easier than in the past for you to fulfill these requirements, by providing interface for doing so. Edit the target, and switch to the Summary tab; there are spaces where for an iPhone app you can drag-and-drop normal and double-resolution icons, and normal and double-resolution launch images, and for an iPad app you can drag-and-drop an iPad icon along with portrait and landscape launch images.
At various stages, you can also obtain validation of your app to confirm that you haven’t omitted certain requirements. For example, by default, a new project’s Release build configuration has the Validate Build Product build setting set to Yes. Thus, when I do a build of the Empty Window app we’ve developed in previous chapters, if that build uses the Release build configuration (or the Distribution build configuration duplicated from it), Xcode warns that the app has no icon. When you submit your app to the App Store, it will be subjected to even more rigorous validation.
An icon ...