Iconomy creates a gorgeous realtime preview of your icon of how it will look on the target device. No need to integrate icons into your App and building/starting it all over again to see how it looks. All necessary retina versions will be created. You can even batch resize or tint your icons directly in the App without altering the original.
You can directly export into an existing Asset Catalog file or drag your icons into Xcode. Of course you can save them into a folder or drag them anywhere you want. The naming of the output files will be automatically done for you.
Iconomy contains over 50 resize templates (resulting in over 100 predefined icon, launch screen or marketing graphics sizes) and you can easily create your own resize templates if needed.
Note: Now requires OS X 10.13 or later