function ReplaceTinyThumb() {
  imgTags = document.getElementsByTagName("img");
  for (i=0; i<imgTags.length; i++) {
     var old_src = imgTags[i].src ;
     var re = /Tiny/ ;
     if(re.test(old_src)) { 
        imgTags[i].src= old_src.replace("Tiny", "Thumb") ;
     }
  }
}