What size are iOS app home screen icons?
App icons designed for the iOS home screen should be the following size (in pixels):
iPhone and iPod touch Retina display: 120 x 120
iPhone and iPod touch standard resolution: 60 x 60
iPad Retina display: 152 x 152
iPad standard resolution: 76 x 76
Developers creating a universal app are required to submit icons in all four resolutions, to ensure the icon displays properly on each device home screen.
iOS will automatically apply a mask to round the app icon corners when it displays on the home screen.