JSFiddle - React, Tailwind, and code Playground
HTML
<div class="gallery">
<img class="maxwidth" id="switcher" src="http://www.addictedtoibiza.com/wp-content/uploads/2012/12/example.png" style="width:300px"/>
</div>
<div class="thumbs">
<ul class="galleryThumbs">
<li class="gallery">
<img class="thumb" src="http://www.addictedtoibiza.com/wp-content/uploads/2012/12/example.png" style="width:120px" />
</li>
<li class="gallery">
<img class="thumb" src="http://www.funnydogsite.com/pictures/Flying_Dog_Is_Flying.jpg" style="width:120px" />
</li>
</ul>
</div>
JavaScript
var imageName = ["http://www.addictedtoibiza.com/wp-content/uploads/2012/12/example.png", "http://www.funnydogsite.com/pictures/Flying_Dog_Is_Flying.jpg"];
$("img.thumb").click(function () {
console.log($("img.thumb").index(this));
var imageUrl=imageName[$("img.thumb").index(this)];
console.log(imageUrl);
$("#switcher").attr("src", imageUrl);
});