At Admin Panel -> Settings -> Switches, the "new/updated icons" switch enables icons which indicate that a article is new, that a article has been updated recently, or that a category has new articles in it. These icons appear next to the category/article name in the articles. The icons are actually just yellow text that says new or updated, not graphics anymore. The template variables are {LINKNEW}, {LINKISUPDATED} and {CATHASNEW} -- used in the article bit and category bit templates. If you want to restyle them, they all use the CSS classes icons and updatedcontent.