JSFiddle - React, Tailwind, and code Playground

HTML

<button id="addImages">Load Images</button>
<div id="container">
    <img data-src="http://lorempixel.com/200/200/nightlife" />
    <noscript>
        <img data-src="http://lorempixel.com/200/200/nature" />
    </noscript>
</div>

CSS

img {
    clear: both;
}

JavaScript

function imagePopulate(within, attr) {
    within = within && within.nodeType == 1 ? within : document;
    attr = attr || 'data-src';
    var images = within.getElementsByTagName('img');
    for (var i = 0, len = images.length; i < len; i++) {
        if (images[i].parentNode.tagName.toLowerCase() !== 'noscript') {
            images[i].src = images[i].getAttribute(attr);
        }
    }
}

document.getElementById('addImages').onclick = function(){
    imagePopulate();
};