This project has less practical value that I'd like to admit, but I decided to go down the rabbit hole of trying to figure out how to create simple GUI for a bash script. This script takes a retina image and down converts into a plethora of formats. Perhaps one day this could be wedged into a straightforward Xcode project that gives it a real GUI and thus more options. I merely ported my my CodeKit 3 hook to an independent shell script and added Zenity after exploring a few options. Notably, there is no error catching.

Dependancies

    brew install imagemagick --with-openjpeg
    brew install webp
    brew install mozjpeg
    brew install zenity

GitHub Jist