It's not that big a thing but thought it might be of interest to some of you. If you are running D7, go to www.pingdom.com, click on tools and enter you're URL and see what comes up as not found. It will be the 2 URLs in red. Tried it on a few sites and they were all the same.
/templates/base/css/indicator.gif
/plugins/jquery/themes/menuarrow.gif
