If this launch storyboard image is required, then you can create it and include it in your folder with your main.lua. We did a tutorial on this a ways back:
https://coronalabs.com/blog/2014/10/21/tutorial-building-multi-screen-launch-images-using-xcode-6/
Keep in mind, this was written in the days of Xcode 6, I’m sure the interface and prompts and such are different with Xcode 8, but with a little Google searching you should be able to adapt the concept to a modern Xcode. Then add a bit to your build.settings and you will be using Storyboard based launch images instead of the bazillion fixed sized PNG images and that big table in your build.settings.
Rob