function xfade(parent_div_id, pause_time, fade_time, resize_imgs) {
	var imgs = [];
	var current_div_num=0;

	/* rotation */
	function perform_fade() {
		var last_div_num = current_div_num;
		current_div_num = (current_div_num + 1) % imgs.length;
		new Effect.Parallel([
			new Effect.Fade(imgs[last_div_num], { 'sync': true, 'from': 1.0, 'to': 0.0 }),
			new Effect.Appear(imgs[current_div_num], { 'sync': true, 'from': 0.0, 'to': 1.0 }) ],
         { 'duration': fade_time});
	}

	/* setup */
	function start_me_up() {
		var parent_div = $(parent_div_id);
		if (!parent_div) return false;
		var parent_width = parent_div.scrollWidth;
		var parent_height = parent_div.scrollHeight;
		var parent_aspect_ratio = parent_width/parent_height;
		/* Get the images to rotate */
		imgs = $$('div#' + parent_div.id + ' .fade-item');
		if (imgs.length == 0) return false;
		if (resize_imgs) {
			/* Size and center each image */
			for (var i=0 ; i < imgs.length ; i++) {
				var img = imgs[i];
				var img_width = img.width;
				var img_height = img.height;
				/* If the image has never been visible, IE will not set or show the width/height. */
				if (img_width==0) {
					var img_proxy = new Image();
					img_proxy.src = img.src;
					img_width = img_proxy.width;
					img_height = img_proxy.height;
				}
				var img_aspect_ratio = img_width/img_height;
				var scale_factor = 1;
				if (img_width > parent_width || img_height > parent_height ||
							(img_width < parent_width && img_height < parent_height)) {
					/* scale image down or up */
					if (img_aspect_ratio > parent_aspect_ratio) {
						scale_factor = parent_width/img_width;
					} else {
						scale_factor = parent_height/img_height;
					}
				}
				if (img_width == 0 && false) {
					alert("Scale factor of: " + scale_factor + "\n"+
								"parent width: " + parent_width + "px\n" +
								"parent height: " + parent_height + "px\n" +
								"img width: " + img_width + "px\n" +
								"img height: " + img_height + "px\n");

				} else if (img_width > 0 && img_height > 0 && scale_factor != 1) {
					img.width = Math.round(img_width * scale_factor);
					img.height = Math.round(img_height * scale_factor);
					if (img.width < parent_width) {
						img.style.left = Math.round((parent_width-Math.round(img_width * scale_factor))/2).toString()+'px';
					}
					if (img.height < parent_height) {
						img.style.top = Math.round((parent_height-Math.round(img_height * scale_factor))/2).toString()+'px';
					}
				}
			}
		}
		setInterval(perform_fade,pause_time*1000);
		Effect.Appear(imgs[current_div_num], { 'duration': fade_time, 'from': 0.0, 'to': 1.0 });
	}

	add_body_onload(start_me_up);
}