Specify a 3x scale image you want to use in an app you're making with Xcode, and this will output a valid .iconset bundle to drop into your filesystem
This project requires Pillow, an updated fork of the Python Imaging Library. You can learn how to install it in their documentation, but the TL;DR is that you can probably just run pip install Pillow. This project also requires Python 3.6 or newer.