function slideShow() {
	//set up variables 
	images = new Array (
               "url(Images/1_one.jpg)",
		"url(Images/2_two.jpg)",
		"url(Images/3_three.jpg)",
		"url(Images/4_four.jpg)",
		"url(Images/5_five.jpg)",
		"url(Images/6_six.jpg)",
		"url(Images/7_seven.jpg)",
		"url(Images/8_eight.jpg)",
		"url(Images/9_nine.jpg)",
		"url(Images/10_ten.jpg)",
		"url(Images/11_eleven.jpg)",
		"url(Images/12_twelve.jpg)",
		"url(Images/13_thirteen.jpg)",
		"url(Images/14_fourteen.jpg)",
		"url(Images/15_fifteen.jpg)",
		"url(Images/16_sixteen.jpg)",
		"url(Images/17_seventeen.jpg)",
		"url(Images/18_eighteen.jpg)",
		"url(Images/19_nineteen.jpg)",
                "url(Images/20_twenty.jpg)",
                "url(Images/21_twenty_one.jpg)",
		"url(Images/22_twenty_two.jpg)"
	);
	//alert (images.length);
	opacity = 1;
	i=0;
	document.getElementById("pictureHolder").style.backgroundImage = images[i];
	//wait 3 seconds
	setInterval("i++; if (i>(images.length-1)) i=0; changeImage(i);", 5000);

}
function changeImage(i) {
	//reduce opacity
	id = setInterval("reduceOpacity(opacity=opacity-0.05)",1000/38);
}

function reduceOpacity (opacity) {
	if (opacity < 0.2) {//opacity = very low?
		/*document.getElementById("pictureHolder").style.opacity = 0;
		document.getElementById("pictureHolder").style.filter = "alpha(opacity = 0)";*/

		//stop executing the set interval instruction
		clearInterval (id);
		//change background
		document.getElementById("pictureHolder").style.backgroundImage = images[i];
		//increase Opacity
		id=setInterval("increaseOpacity(opacity = opacity + 0.05)",1000/38);
	}
	else {
		var filterString = "alpha(opacity ="+opacity * 100+")";
		document.getElementById("pictureHolder").style.opacity = opacity;
		document.getElementById("pictureHolder").style.filter = filterString;
	}
}

function increaseOpacity (opacity) {
	if(opacity >0.9) {//opacity high
		document.getElementById("pictureHolder").style.opacity = 1;
		document.getElementById("pictureHolder").style.filter = "alpha(opacity = 100)";
		//stop executing the set interval instruction
		clearInterval (id);
	}
	else {
		var filterString = "alpha(opacity ="+opacity * 100+")";
		document.getElementById("pictureHolder").style.opacity = opacity;	
		document.getElementById("pictureHolder").style.filter = filterString;
	}
}