tuanphan - So this did not work. What did work, kinda, is the JS you sent me from codpen :
function changeBg() {
var backgrounds = ["https://images.unsplash.com/photo-1502741338009-cac2772e18bc?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1950&q=80", "https://images.unsplash.com/photo-1498557850523-fd3d118b962e?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=1950&q=80", "https://images.unsplash.com/photo-1566400628146-ae8f27849e90?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2100&q=80"];
var imgShown = document.body.style.backgroundImage;
var newNumber = Math.floor(Math.random()*backgrounds.length);
document.body.style.background = 'url('+backgrounds[newNumber]+')';
}
window.onload = changeBg;
When I mean "kinda worked", the images previewed in "Safe Mode" while editing the page in Squarespace. Once I saved the page, logged out and opened it in another browser there was nothing where the code block is located. I did check to make sure that Javascript is working.
Again, I thank you for your time and help!