function showpicture(w, h, img, evtObj){
  var newImage = new Image();
  newImage.src = img;
  x=evtObj.clientX;
  y=evtObj.clientY+5;
  x -= w/2;
  y -= h/2;
  newWin = window.open("/show_img.php?img="+img+" &w="+w+"&h="+h, null, "width="+w+", height="+h+", top="+y+", left="+x+", resizable=0");
}