Missing CSS image dir causing unnecessary 404 log entries

Line 5 of style.css reads:

.inside p.loading{background:transparent url(../images/spinning_wheel.gif) 50% 90% no-repeat scroll;margin-top:30px;}

… but there is no images directory in the parent directory of style.css.

http://ww.wp.xz.cn/plugins/wp-slimstat-dashboard-widgets/