App Icon Template for creating correct iOS and Android icon assets.
Design your icon in the size your users will view it. This icon will automatically be scaled to all the required sizes, both for iOS and Android.
See how the icon will look in all the sizes that are required. Some things might work well in a small size, but not when it's viewed at a larger scale.
Your icon is always competing with other apps. See how your icon works in the right context, on the home screen and in the app stores.
When you are happy with the icon, you can export everything with the tap of a button. Neatly organised in folders and named correctly.