I'm currently developing an application for iPhone with iOS7, only. From what I read, for iPhone with iOS7, there is no support for older devices than iPhone4. If that's the case, when it comes to images, all I need is retina images (@2x).
Can I submit to the App Store, an app with only retina images, since the app's minimal requirement is retina devices ?
Thank you.
Possible duplicate of Can I dump my non-Retina Images for a iOS7 only app?
Anyway, as long as I know you don't need @2x version of your images as long as you don't support old displays, but remember that your images as to be double width and height, then if you have a 100x100px UIImageView, you need to load a 200x200px image to meet retina resolution.
EDIT: To explain in deep.
Actually, iPad 2 and iPad mini 1st generation run iOS 7 and doesn't have retina display. Anyway using @2x images it is not mandatary. You can just use double size images and set your UIImageViews' contentMode to UIViewContentModeScaleToFill to fit your needs.
PROS -> smaller bundle
CONS -> worst performaces
来源：https://stackoverflow.com/questions/22019856/ios7-app-submission-with-only-2x-retina-images