JSFiddle - React, Tailwind, and code Playground

HTML

<div class="home-photo">Changing Photo</div>

CSS

.breakfast, .home-photo { 
background-image: url('http://a.abcnews.com/images/Technology/HT_audi_google_jtm_131230_16x9_992.jpg');
background-size: 100%;
width: 100%;
height: 0;
padding-top: 61%;
text-indent: -9999px;}

.lunch, .home-photo { 
background-image: url('https://lh5.googleusercontent.com/-kP_vT8zSArw/UlwcdM3g42I/AAAAAAAASEA/DtsFL3UjZFo/s630-fcrop64=1,000010d3ffffe9f6/tumblr_me8rxmQrvO1rnvhfco1_1280.jpg');
background-size: 100%;
width: 100%;
height: 0;
padding-top: 61%;
text-indent: -9999px;}

JavaScript

var currentTime = new Date().getHours();
if (6 <= currentTime && currentTime < 12) {
if (document.body) {
    document.body.className = "breakfast";
}
}
else {
if (document.body) {
    document.body.className = "lunch";
}
}