I couldn’t find any solid one-stop reference for the different iOS app icon sizes, so here’s a quick summary. This lists out the different icon sizes you’ll need for an app compatible only with retina devices (iPhone 4s and above), running iOS6.1 and above.
App Icon Sizes
- App icon (required for all apps): 120 x 120
- App icon for the App Store (required for all apps): 1024 x 1024
- Spotlight search results icon (recommended): 80 x 80
- Settings icon (recommended): 58 x 58
- Toolbar and navigation bar icon (optional): 44 x 44
- Tab bar icon (optional): 50 x 50
- Web clip icon: 120 x 120
- For iPhone5 and above: 640 x 1136
- For iPhone 4s and iPod touch: 640 x 960
- For all images and icons, the PNG format is recommended. You should avoid using interlaced PNGs.
- The standard bit depth for icons and images is 24 bits—that is, 8 bits each for red, green, and blue—plus an 8-bit alpha channel.
- You don’t need to constrain your palette to web-safe colors.
App Icon Rounded Corners
Please keep in mind, you’re final app icon assets should NOT have rounded corners!
“Note that iOS 7 doesn’t apply shine or a drop shadow to the app icon. And, although iOS 7 still applies a mask that rounds the corners of an app icon, it uses a different corner radius than earlier versions of iOS.” (Source: Apple’s iOS7 Transition Guide)
For more reference, check out Apple’s dev documentation.