function preloadImages(images)
{
	var loaders = new Array();
	for (var i = 0; i < images.length; i++)
	{
		var tmp = new Image();
		tmp.src = images[i];
		loaders.push(tmp);
	}
}

function initaliseNavigation()
{
	var images = document.getElementById('topnav').getElementsByTagName('img');
	
	for(var i = 0; i < images.length; i++)
	{
		if (images[i].src.indexOf('_over.gif') == -1)
		{		
			images[i].onmouseover = function()
			{
				this.src = this.src.substring(0, this.src.lastIndexOf('_')) + '_over.gif';
			}
			
			images[i].onmouseout = function()
			{
				this.src = this.src.substring(0, this.src.lastIndexOf('_')) + '_out.gif';
			}
		}
	}
}