JSFiddle - React, Tailwind, and code Playground

HTML

<div class="post">
    <img src="http://placehold.it/200">
</div>

JavaScript

var img = document.querySelector('div.post img');
var div = document.createElement('div');
div.className = 'imgWrap';
img.parentNode.insertBefore(div, img);
div.appendChild(img);