JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<div>
  <img class="img-responsive" src="http://icons.iconarchive.com/icons/mazenl77/I-like-buttons-3a/512/Cute-Ball-Go-icon.png" class="img-responsive" />
</div>

CSS

div {
  height: 50%; /* doesn't work */
  /* height: <num> px; does work but isn't responsive */
  overflow: hidden;
}