Alfred 3 workflow for making an app icon [icns] based upon the selected file.
- Install alfred-make-appicon workflow.
- All further updates are handled automatically.
In finder, select an image file, which is at least 1024x1024px large, and invoke the alfred file actions, by default the ⌃⌘\ shortcut.
icns file will be created in the same location as the original input file.