Resizing Square

This is an example of the usage of the vw unit.

by Gaurav Singh

HTML

<div class="wrapper">
    <img src="http://cdn.sstatic.net/stackexchange/img/slider/stackoverflow.com.png">
</div>

CSS

img {
    position:fixed;
    top:0;
    bottom:0;
    left:0;
    right:0;
    margin:auto;
    background: #000;
}