function preload() {
	var imgNames = ['home', 'home-over', 'services', 'services-over', 'equipment', 'equipment-over', 'contact', 'contact-over'];
	var imgObjects = [];
	
	for (var i = 0; i < imgNames.length; i++) {
		imgObjects[i] = new Image();
		imgObjects[i].src = '/images/nav-' + imgNames[i] + '.gif';
		
	} 
}

function swapImg(lnk, state) {
	if (state == 'over') {
		document.getElementById('img' + lnk).src = '/images/nav-' + lnk + '-over.gif'; 
	} else {
		document.getElementById('img' + lnk).src = '/images/nav-' + lnk + '.gif'; 
	}
}

addLoadListener(preload);