You want to go to "Customize Journal."

Then, on that page there will be a blue sidebar, and one of the options will be "Custom CSS"

Click that, and paste the code below in the text entry form at the bottom.

Click "Save Changes" and your journal should have a slightly diffrent layout. = )

body {
font-family:Arial, Helvetica, sans-serif;
font-size: 12px;
color:#FFFFFF;
background: url(body.gif) center top repeat-y #2fb3fd; /* background behind main box*/

}

#header-inner {
background-image: url("http://i171.photobucket.com/albums/u285/absinthe34/random/YuePhotobanner.jpg");
height: 200px;
background-position: center right;
background-repeat:no-repeat;
}


#header {
background-image: none;
background-color:#000000;
}