JSFiddle - React, Tailwind, and code Playground

HTML

<body id="body">
    <div id="test"></div>
</body>

CSS

#body {
	background-color:#000;
	background-attachment:fixed;
	background-repeat:no-repeat;
	-moz-background-size: cover;
	-webkit-background-size: cover;
	-o-background-size: cover;
	background-size: cover;
}
#test {
    height:1000px;
}

JavaScript

$(document).ready(function () {
    switchImage();
});

$(window).scroll(function () {
    switchImage();
});

var pics = []; // CREATE PICS ARRAY

//PRELOAD FUNCTION TO SET UP PICS ARRAY IN MEMORY USING IMAGE OBJECT
function preload() {
    for (i = 0; i < arguments.length; i++) {
        pics[i] = new Image();
        pics[i].src = arguments[i];
        //alert("preload " + arguments[i]);
    }
}
preload(
    'http://ingodwetrustthemovie.com/bgImage/100.jpg',
    'http://ingodwetrustthemovie.com/bgImage/101.jpg',
    'http://ingodwetrustthemovie.com/bgImage/102.jpg',
    'http://ingodwetrustthemovie.com/bgImage/103.jpg',
    'http://ingodwetrustthemovie.com/bgImage/104.jpg',
    'http://ingodwetrustthemovie.com/bgImage/105.jpg',
    'http://ingodwetrustthemovie.com/bgImage/106.jpg',
    'http://ingodwetrustthemovie.com/bgImage/107.jpg',
    'http://ingodwetrustthemovie.com/bgImage/108.jpg',
    'http://ingodwetrustthemovie.com/bgImage/109.jpg',
    'http://ingodwetrustthemovie.com/bgImage/110.jpg',
    'http://ingodwetrustthemovie.com/bgImage/111.jpg',
    'http://ingodwetrustthemovie.com/bgImage/112.jpg',
    'http://ingodwetrustthemovie.com/bgImage/113.jpg'
);

function switchImage() {
    var s = $(window).scrollTop()/10;
    var index = Math.floor(s / 5);

    $('body').css('background-image', 'url(' + pics[index].src + ')');
}