Update applications for iPhone 4 Retina Display

I was just wondering how you would go about giving a application the new sharper images for the iPhone 4? i know the SDK already cleans up text and UI elements but how should I go about updating my image UI. Is there a di开发者_Python百科fferent way (like a folder or file extension) to add the new images for the iPhone 4 or should I just go and add 960x640 size images and let the older iPhones scale it down?

There is a very good and complete document from Apple covering just that. Check out the iPhone Application Programming Guide, it has a chapter on that very topic.

Edit: The link