Starting with 2.3.1.9 you can choose between Icons or text for the administration links. To use Icons, change
<portal:StyleSheetCombiner id="StyleSheetCombiner" runat="server" UseIconsForAdminLinks="false" />
to
<portal:StyleSheetCombiner id="StyleSheetCombiner" runat="server" UseIconsForAdminLinks="true" />
Hope this helps,
Joe D.