Código PHP:
echo " <td width='45'><target=\"_blank\" class='menu' onmouseover=this.style.cursor='hand' onClick=window.open('./imagenesup/$enlace',\"\",\"toolbar=0,location=0,status=0,menubar=0,scrollbars=1,target='_blank',resizable=1,width=500,height=500\")><img src=./imagenesup/$enlace onmouseover=this.style.cursor='hand' width='100' height='75' border=0 rel=lightbox></td>";