function cache_images()
{
	var d = document;

	if (d.images)
	{
		if (!d.cached_imgs)
			d.cached_imgs = new Array();
		
		var i, j=d.cached_imgs.length, a=cache_images.arguments;
		
		for (i=0; i<a.length; i++)
			if (a[i].indexOf("#") != 0)
			{
				d.cached_imgs[j] = new Image;
				d.cached_imgs[j++].src = a[i];
			}
	}
}

function swap_images()
{
	var d = document;
	var a = swap_images.arguments;
	var swapsrc = '';
	
	a[0].origsrc = a[0].src;
	
	var dot = a[0].src.lastIndexOf(".");
	var beg = a[0].src.substr(0,dot);
	var ext = a[0].src.substr(dot);
	
	swapsrc = beg+'_on'+ext;
	
	a[0].src = swapsrc;
}

function restore_images()
{
	var d = document;
	var a = restore_images.arguments;
	
	a[0].src = a[0].origsrc;
}

function look_for_swappable_images()
{
	var d = document;
	var di = d.images;
	var filename, dot, beg, ext;
	
	for (var i=0; i < d.images.length; i++)
	{
		if (d.images[i].className=='hover_over')
		{
            d.images[i].onmouseover = function() { swap_images(this); };
            d.images[i].onmouseout = function() { restore_images(this); };
            
			filename = d.images[i].src;

			dot = filename.lastIndexOf(".");
			beg = filename.substr(0,dot);
			ext = filename.substr(dot);
			
			filename = beg+'_on'+ext;
			
			cache_images(filename);
		}
	}
}

look_for_swappable_images();