RoutingError from css background image url

In my css file, I have a css element that has a background image that's defined as

background: url(/images/global/tab-arrow.gif) no-repeat 16px 8px ;

This throws a Routing Error when an element with that class gets rendered

ActionController::RoutingError (No route matches "/images/" with {:domain=>"localhost", :method=>:get, :subdomain=>nil, :host=>"localhost"}):     /vendor/rails/actionpack/lib/action_controller/routing/ recognition_optimisation.rb:67:in `recognize_path'

It works fine when the image is copied into the public/images directory but doesn't like it when the image happens to be in a sub directory. This looks like the Rails Routing is trying to treat this url as a restful resource and I was wondering if anyone else has run into this problem and how to go about resolving it.

Thanks in advance.