Mine

function saveThumbnail($saveToDir, $imagePath, $imageName, $max_x, $max_y) {
   preg_match("'^(.*)\.(gif|jpe?g|png)$'i", $imageName, $ext);
   switch (strtolower($ext[2])) {
       case 'jpg' :
       case 'jpeg': $im  = imagecreatefromjpeg ($imagePath);
                     break;
       case 'gif' : $im  = imagecreatefromgif  ($imagePath);
                     break;
       case 'png' : $im  = imagecreatefrompng  ($imagePath);
                     break;
       default    : $stop = true;
                     break;
   }
  
   if (!isset($stop)) {
       $x = imagesx($im);
       $y = imagesy($im);
  
       if (($max_x/$max_y) < ($x/$y)) {
           $save = imagecreatetruecolor($x/($x/$max_x), $y/($x/$max_x));
       }
       else {
           $save = imagecreatetruecolor($x/($y/$max_y), $y/($y/$max_y));
       }
       imagecopyresized($save, $im, 0, 0, 0, 0, imagesx($save), imagesy($save), $x, $y);
      
       imagegif($save, "{$saveToDir}{$ext[1]}_thumb.gif");
       imagedestroy($im);
       imagedestroy($save);
   }
}
saveThumbnail("../images/uploads/", "../images/uploads/$file1_name", $file1_name, 179, 159);