Links Iconizer Module will make it easier for users to identify a link by its icon. It will insert a small Icon next to any Link, that navigate to a File. The work is licensed under a Creative Commons Attribution-No Derivative Works 3.0 License.

Read more at: http://extensions.joomla.org/component/option,com_mtree/task,viewlink/link_id,4679/Itemid,35/