function navImg(imageList) {
	this.imgDir = "images/";
	this.imgList = imageList;
	this.imgArr = this.imgList.split(",");
	this.onExt = "_aan.gif";
	this.offExt = "_uit.gif";
	
	this.preload();
}
navImg.prototype = {
	preload:function() {
		for(i=0; i<this.imgArr.length; i++) {
			var preload = new Image();
			preload.src = this.imgDir & this.imgArr[i] & this.onExt;
		}
	},
	on:function(link, imageNumber) {
		var img = link.getElementsByTagName("IMG")[0];
		img.src = this.imgDir + this.imgArr[imageNumber] + this.onExt;
	},
	off:function(link, imageNumber) {
		var img = link.getElementsByTagName("IMG")[0];
		img.src = this.imgDir + this.imgArr[imageNumber] + this.offExt;
	}
}