#!/usr/bin/perl

    $count = 1;
    foreach (glob "*.jpg")
    {
      if ($_ !~ /\Q.jpg/i) { next; }
      if ($_ =~ /^tn_/i) { next; }
      $str = sprintf("%02d.jpg",$count++);
      if ($str eq $_) { next; }
      rename($_, $str);
      print "Renamed $_ to $str\n";
    }
    if ($count==1) { print "No .jpgs found or none needed to be renamed.\n"; }