Note: After saving, you have to bypass your browser's cache to see the changes. Internet Explorer: press Ctrl-F5, Mozilla: hold down Shift while clicking Reload (or press Ctrl-Shift-R), Opera/Konqueror: press F5, Safari: hold down Shift + Alt while clicking Reload, Chrome: hold down Shift while clicking Reload.
addOnloadHook(function(){if((wgNamespaceNumber==6)){mw.util.addPortletLink('p-tb',"http://toolserver.org/~multichill/coordinates.php?template=location&wiki=commons.wikimedia.org&page="+encodeURIComponent(mw.config.get('wgPageName')),'Geo tag this','t-geotag',"Add a location template to this file",'1');}});