if(document.images){
//preload
var btArtOff = new Image; btArtOff.src = "../img/nav-art-off.gif";
var btArtOn = new Image; btArtOn.src = "../img/nav-art-on.gif";
var btArtistOff = new Image; btArtistOff.src = "../img/nav-artist-off.gif";
var btArtistOn = new Image; btArtistOn.src = "../img/nav-artist-on.gif";
var btExhibitsOff = new Image; btExhibitsOff.src = "../img/nav-exhibits-off.gif";
var btExhibitsOn = new Image; btExhibitsOn.src = "../img/nav-exhibits-on.gif";
var btContactOff = new Image; btContactOff.src = "../img/nav-contact-off.gif";
var btContactOn = new Image; btContactOn.src = "../img/nav-contact-on.gif";
var btLinksOff = new Image; btLinksOff.src = "../img/nav-links-off.gif";
var btLinksOn = new Image; btLinksOn.src = "../img/nav-links-on.gif";
var btHomeOff = new Image; btHomeOff.src = "../img/nav-home-off.gif";
var btHomeOn = new Image; btHomeOn.src = "../img/nav-home-on.gif";
}

function chgImg(origImg,newImg)
{
	if (document.images){
	document[origImg].src = eval(newImg + ".src")
	}
}