window.onload = rolloverInit;

function rolloverInit() {

	for (var i=0; i<document.images.length; i++) {

		if (document.images[i].parentNode.tagName == "A") {

			setupRollover(document.images[i]);

		}

	}

}

function setupRollover(thisImage) {

	thisImage.outImage = new Image();
	thisImage.outImage.src = thisImage.src;
	thisImage.onmouseout = rollOut;

	thisImage.overImage = new Image();
	thisImage.overImage.src = "http://stevetoase.co.uk/images/" + thisImage.id + "Lit.jpg";
	thisImage.onmouseover = rollOver;

}

function rollOver() {

	this.src = this.overImage.src;

}

function rollOut() {

	this.src = this.outImage.src;

}