I'm not sure it's new for you but I just discovered how to add background image to .userTitle .userSubtitle .entryHeader .sideHeader and other similar fields. It looks like this:
.userTitle { text-align: center; font-size: 20px; padding-bottom: 3px; background: #FFFFFF url(http://images.rambler.ru/m3/macos/i-bgtop.gif) repeat-x; }
Experiment and enjoy!
:)