HTML/CSS: Intrinsic Ratios image solution for responsive images

gistfile1.html

<div class="img-container">
<img src="http://cdn3.spiegel.de/images/image-545702-breitwandaufmacher-penw.jpg">
</div>

gistfile2.css

.img-container {
  background: red;
	position: relative;
	height: 0;
	padding-bottom: 37.209302326%; /* 43:16 ratio */
	overflow: hidden;
}

.img-container img {
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%
}