I'm impressed you are doing it from your phone! Okay, here is some CSS you can use:

#title span { display: none; }
#title {
width: 718px;
height: 503px;
background-image: url(http://i1181.photobucket.com/albums/x428/knowmefirst0/0807262054271bp_glass_-2.jpg);
background-repeat: none;
}

Put it in the big box here:

http://www.dreamwidth.org/customize/options?group=customcss

And you should be good. Let me know if you need any more help!