RandomSplash

http://randomsplash.jshawl.com/

Is the easiest way to get a random image from http://unsplash.com/

You can use it as an inline image:

<img src='http://randomsplash.jshawl.com/'>

Or as a background image:

.container{
    background:url(http://randomsplash.jshawl.com/);
}