window.onload=function(){
  var gallery;
  if(gallery=document.getElementById('gallery')){
    var href=gallery.getElementsByTagName('a');
    for(var i=0;href[i];i++){
      href[i].onclick=function(){return showImg(this);}
    }
  }
}
function showImg(e){
  var screen_width=screen.availWidth;
  var screen_height=screen.availHeight;
  var my_width=740;
  var my_height=760;
  var my_left=(screen_width-my_width)/2;
  var my_top=(screen_height-my_height)/2;
  var parameters='width='+my_width+',height='+my_height+',top='+my_top+',left='+my_left+',scrollbars=1';
  var w=window.open(e.href,'img',parameters);
  w.focus();
  return false;
}