The icon images are background images, not image tags.
Any reason you don't want to use a class name instead, you can create your own style.css
.icon-add { background: url('../icons/add_cross.png')}
.icon-address { background: url('../icons/address.png')}
.icon-admin { background: url('../icons/folder_wrench.png')}
.icon-attach { background: url('../icons/pclip_add.png')}
or you can also use the aicon feature which does not require a css rule to be created:
http://www.jeasyui.com/forum/index.php?topic=4234.msg10828#msg10828Cheers