[css] Insert a background image in CSS (Twitter Bootstrap)

For more modularity and in case you have many background images that you want to incorporate wherever you want you can for each image create a class :

.background-image1  
{
background: url(image1.jpg);
 }
.background-image2  
{
background: url(image2.jpg);
 }

and then insert the image wherever you want by adding a div

<div class='background-image1'>
    <div class="page-header text-center", style='margin: 20px 0 0px;'>
         <h1>blabaaboabaon</h1>
    </div>
</div>