function centralizaImagens(id, w, h){
	var div = document.getElementById(id);
	if(div){
		var spans = div.getElementsByTagName('span');
		for(var i = 0; i < spans.length; i++){
			if(spans[i]){
				var img = spans[i].getElementsByTagName('img');
				if(img[0]){
					var x = w - img[0].width;
					var left = Math.round(x/2);
					
					var y = h - img[0].height;
					var top = Math.round(y/2);
					
					img[0].style.top  = top + "px";
					img[0].style.left = left + "px";
				}
			}
		}
	}
}