var imagePrefix = "/img/";

function preload(newImages){
	if(!newImages){
		var newImages = new Array();	/* Initialize Image names */
	}

	for (i = 0; i < newImages.length; i++){  /* here walk through images array and preload */	
		newImage = new Image();
		eval("newImage.src = '" + imagePrefix + newImages[i] + "_on.gif';");
		
		// alert("newImage.src = '" + imagePrefix + newImages[i] + "_on.gif';");
	}
}

function imgOn(imgName, fileName) {
	if(!fileName){
		fileName = imgName;
	}
	
	if (document.images) {    
		eval("document.images['" + imgName + "'].src = '" + imagePrefix + fileName + "_on.gif'");
	}
}

function imgOff(imgName, fileName) {
	if(!fileName){
		fileName = imgName;
	}
	
	if (document.images) {    
		eval("document.images['" + imgName + "'].src = '" + imagePrefix + fileName + ".gif'");
	}
}