How to add a background image??

I've looked everywhere and cant find out how to add a background image to my site..

I've found out how to add a image to my columns,
I've found out how to add a image to my text section,
BUT NOT TO THE BACKGROUND!!

My site is lfswear.com

dddmx3:

I've looked everywhere and cant find out how to add a background image to my site..

I've found out how to add a image to my columns,
I've found out how to add a image to my text section,
BUT NOT TO THE BACKGROUND!!

My site is lfswear.com

in your stylesheet.css file, find the body tag and add background-image: url(../images/yourimage.jpg); to it...
as below,

body {
    margin: 0;
    font-family: verdana, arial, helvetica, sans-serif;
    font-size: 62.5%;
    color: #000000;
    background-color: #e5edf5;
    background-image: url(../images/yourimage.jpg);
}

Thank you, but How do I make the white part 80% transparent

and the header?