function newImage(arg) {
	newImg = new Image();
	newImg.src = arg;
	return newImg;
}

//Preload common images
var imageArray = new Array()
imageArray["uparrow-off"] = newImage("images/uparrow-off.png")
imageArray["uparrow-on"] = newImage("images/uparrow-on.png")
imageArray["uparrow-click"] = newImage("images/uparrow-click.png")
imageArray["downarrow-off"] = newImage("images/downarrow-off.png")
imageArray["downarrow-on"] = newImage("images/downarrow-on.png")
imageArray["downarrow-click"] = newImage("images/downarrow-click.png")

imageArray["aboutus"] = newImage("images/aboutus.gif")
imageArray["aboutus-Over"] = newImage("images/aboutus-Over.gif")
imageArray["aboutus-Sel"] = newImage("images/aboutus-Sel.gif")
imageArray["aboutus-SelOver"] = newImage("images/aboutus-SelOver.gif")

imageArray["contactus"] = newImage("images/contactus.gif")
imageArray["contactus-Over"] = newImage("images/contactus-Over.gif")
imageArray["contactus-Sel"] = newImage("images/contactus-Sel.gif")
imageArray["contactus-SelOver"] = newImage("images/contactus-SelOver.gif")

imageArray["portfolio"] = newImage("images/portfolio.gif")
imageArray["portfolio-Over"] = newImage("images/portfolio-Over.gif")
imageArray["portfolio-Sel"] = newImage("images/portfolio-Sel.gif")
imageArray["portfolio-SelOver"] = newImage("images/portfolio-SelOver.gif")


function imgSwap(oImg, strAction) {
	/*
	oImg is a reference to the image object ('this' in javascript)
	strAction is the part of the filename after the '-', e.g. over, on, off, SelOver	
	*/
	var strExtension
	var currentImg = strExtension = oImg.src
	//strExtension = strExtension.substr(strExtension.lastIndexOf("."))
	if (currentImg.lastIndexOf("-") > 0) {
		currentImg = currentImg.substring(currentImg.lastIndexOf("/")+1, currentImg.lastIndexOf("-"))
	} else {
		currentImg = currentImg.substring(currentImg.lastIndexOf("/")+1, currentImg.lastIndexOf("."))
	}
	if (strAction.length > 0) {
		oImg.src = imageArray[currentImg + "-" + strAction].src
	} else {
		
		oImg.src = imageArray[currentImg].src
	}
}

/*
Swapping Big images
*/
var currentPic = "1";

function swapPic(imgNumber) {
	document.getElementById("BigPic").src = imageArray[imgNumber].src;
	//now alter alt text for selected minipic
	if (document.getElementById("minipic" + imgNumber)) {
		document.getElementById("minipic" + imgNumber).alt = "Picture " + imgNumber + " (current)";
		
		if (document.getElementById("minipic" + currentPic)) {
			document.getElementById("minipic" + currentPic).alt = "Picture " + currentPic;
		}		
	}
	currentPic = imgNumber;
	//now change alt text
	document.getElementById("BigPic").alt = altTextArray[imgNumber];
	
}

function setInitialFocus() {
	//document.getElementById("divText").focus();
}