Just Replace the URL with the url of the image that you want to apear on your background
Paste this code in the CSS area.


.right_column .column_content {
width:300px;
height:auto;
margin: 0 0 9px 0;
background-color: transparent;
background-image: url(URL);
border: transparent;
border-top:0;
overflow: hidden;
}

.right_column_content {
width:300px;
height:auto;
background-color: transparent; 
background-image: url(URL);
border: transparent;
border-top:0;
overflow: hidden;
padding: 10px 0 0 0;
margin: 0 0 10px 0;
}