How do I replace that box with a picture?

<style type="text/css">
table table table td {vertical-align:top ! important;}
span.blacktext12 {
visibility:visible !important;
background-color:transparent;
background-image:url("YOUR PICTURE URL HERE");
background-repeat:no-repeat;
background-position:center center;
font-size:0px; letter-spacing:-0.5px;
width:435px; height:75px; display:block !important; }
span.blacktext12 img {display:none;}
</style>

just replace the bolded.