Make sure to have everything installed that is needed
npm install -g yo generator-rn-toolbox
To generate your icons, the generator uses ImageMagick. On macOS, you can install it with:
brew install imagemagick
Have a single icon file at the ready somewhere. 200x200px is sufficient.
The from the command line you can run:
yo rn-toolbox:assets --icon <path to your icon>
# For instance
yo rn-toolbox:assets --icon ../icon.png
You will be presented with some prompts, just let it overwrite the asset files that are already present in xcode
thats it
I will let the rest be magic ^_^ the original website tutorial is below https://blog.bam.tech/developper-news/change-your-react-native-app-icons-in-a-single-command-line