Different Images on Refresh

https://parakeet-chrysalis-lnzs.squarespace.com/

password: madcap

Hi! My client would like the large, main gallery on her home page (which is currently set to automatically transition between slides), to only show 1 image at a time, and then show a new image on reload or revisit. I've seen past posts in the forum about this, but I'm confused. Down below is the code I've seen, but what do I need to replace in the code? Just the image URLs? And I think it needs to go into code injection > footer? 

<script>
document.addEventListener('DOMContentLoaded', function() {
  var images = [
    'https://randomwordgenerator.com/img/picture-generator/54e9d1454b5ba914f1dc8460962e33791c3ad6e04e507440752b7edc9649c2_640.jpg',
    'https://randomwordgenerator.com/img/picture-generator/50e2dc464e4faa0df7c5d57bc32f3e7b1d3ac3e45658724e77267bd493_640.jpg',
    'https://randomwordgenerator.com/img/picture-generator/50e2dc464e4faa0df7c5d57bc32f3e7b1d3ac3e45658724e77267bd493_640.jpg',
    'https://randomwordgenerator.com/img/picture-generator/nick-dunlap-h65WkTvyWJY-unsplash.jpg'
].sort( () => .5 - Math.random() );
    var randImage = images[0];
    document.querySelector(".homepage article.sections section:first-child .section-background img").src = randImage;
    document.querySelector(".homepage article.sections section:first-child .section-background img").setAttribute("srcset", "");
});

</script>

The code will target Homepage First Section Background Image

change it to another image on page load.