function Zoom (imagen){
var imgTemp = new Image();
var tmp = new Date();
var suffix = tmp.getTime();
imgTemp.src = imagen + '?' + suffix;
imgTemp.onload = function() {
hh = imgTemp.width;
vv = imgTemp.height;
html = "Imagen![](" + imagen + ")
";
hor=screen.width; ver=screen.height; h=(hor-(eval(hh)+16))/2; v=((ver-(eval(vv)+16))/2)-40;
valores="toolbar=no,location=no,menubar=no,directories=no,status=no,width="+(eval(hh)+16)+",height="+(eval(vv)+16)+",left="+h+",top="+v;
ventana=window.open("","ventana",valores);
ventana.document.writeln(html);
}
}