billboard script here: https://vesta.janusxr.org/files/bepis/scripts/billboard.js
chromakey script here: https://vesta.janusxr.org/files/bepis/shaders/v60_cutout_chromakey.txt
To change the chroma key, edit chromakey_col="#0 1 0 0.5" which the first 3 values represent color and the third is the threshold.
Credits to spyduck and firefoxg for huge help to get it working.