Why i cannot use background-image: url("omg/1.jpg"); to using local images？ : The code is like below. I have already put the image "1.jpg" into that file

name "img". But in my website, this image doesn't show up. However, i found 

that if i use the images from Internet, it will show up. Could someone 

figure out the problem? Thanks.

<!-- begin snippet: js hide: false -->

<!-- language: lang-css -->

    #banner
    {
      background-image: url("img/1.jpg");
    }

<!-- end snippet -->
