I am trying to display an image by using css. The code isn't working. Nothing is displayed.

I have tried this code;

Code:
#head-photo {background-image: url('http://what-do-christians-believe.co.uk/wpimages/people-2d.jpg');
             max-width: 30em;
             max-height: 15em;}
I currently have this code in the css file;

Code:
#head-photo {maximum-width: 62.50em;
             maximum-height: 14.70em;
             margin: 0 auto;
             background: url(http://www.what-do-christians-believ.../people_2d.jpg) no-repeat center scroll;
}
The html code for the image is;

HTML Code:
<div id="head-photo"> ///also tried putting </div> here
          </div>
You can see what happens here. The image in the text box is in the html file. For some reason the larger image was rejected and the validation said to use css instead.