PHP image resize script (that could be better)

<?php

  /* ----------[ func IMAGE_RESIZE_DIMENSIONS ]----------*/
  function image_resize_dimensions($source_width,$source_height,$thumb_width,$thumb_height)
  {

    $source_ratio = $source_width / $source_height;
    $thumb_ratio = $thumb_width / $thumb_height;
    // Ratio is Taller
    if ($thumb_ratio > $source_ratio)
    {
      $result_height = $thumb_height;
      $result_width = $thumb_height * $source_ratio;
    }
    // Ratio is Wider
    elseif ($thumb_ratio < $source_ratio)
    {
      $result_width = $thumb_width;
      $result_height = $thumb_width / $source_ratio;
    }
    // Ratio the Same
    elseif($thumb_ratio == $source_ratio)
    {
      $result_height = $thumb_height;
      $result_width = $thumb_width;
    }

    return array('x'=>$result_width,'y'=>$result_height);
  }

  /* ----------[ func IMAGE_RESIZE ]----------*/
  function image_resize_jpg($image = FALSE,
                            $filename = FALSE,
                            $thumb_width,
                            $thumb_height,
                            $maximize = FALSE,
                            $quality = 75,
                            $image_object = FALSE)
  {
    if (is_resource($image_object) === true)
    {
      $source_width = imagesx($image_object);
      $source_height = imagesy($image_object);
      $thumb_source = $image_object;
    }
    else
    {
      list($source_width, $source_height, $source_type) = @getimagesize($image);
      switch($source_type)
      {
        case 1:
          $thumb_source = imagecreatefromgif($image);
          break;
        case 2:
          $thumb_source = imagecreatefromjpeg($image);
          break;
        case 3:
          $thumb_source = imagecreatefrompng($image);
          break;
        default:
          return false;
          break;
       }
    }

    if ($maximize === TRUE)
    {

      $target_width = $thumb_width;
      $target_height = $thumb_height;

      if ($thumb_width && ($source_width < $source_height))
      {
         $thumb_width = ($thumb_height / $source_height) * $source_width;
      }
      else
      {
         $thumb_height = ($thumb_width / $source_width) * $source_height;
      }

      if ($thumb_height < $target_height)
      {
        $multiply_height = $target_height / $thumb_height;
        $thumb_height = $thumb_height * $multiply_height;
        $thumb_width = $thumb_width * $multiply_height;
      }
      if ($thumb_width < $target_width)
      {
        $multiply_width = $target_width / $thumb_width;
        $thumb_height = $thumb_height * $multiply_width;
        $thumb_width = $thumb_width * $multiply_width;
      }

      $thumb_height = ceil($thumb_height);
      $thumb_width = ceil($thumb_width);

    }
    else if ($source_width > $thumb_width or $source_height > $thumb_height)
    {

      $dimensions = image_resize_dimensions($source_width,$source_height,$thumb_width,$thumb_height);
      $thumb_width = $dimensions['x'];
      $thumb_height = $dimensions['y'];
      $target_width = $dimensions['x'];
      $target_height = $dimensions['y'];

    }
    else // Resize Nothing
    {
      $thumb_width = $source_width;
      $thumb_height = $source_height;
      $target_width = $source_width;
      $target_height = $source_height;
    }

    $thumb_image = imagecreatetruecolor($thumb_width,$thumb_height);

      //imagecopyresampled($thumb_image, $thumb_source, 0, 0, 0, 0, $thumb_width, $thumb_height, $source_width, $source_height);
    fastimagecopyresampled($thumb_image, $thumb_source, 0, 0, 0, 0, $thumb_width, $thumb_height, $source_width, $source_height);

    $target_image = imagecreatetruecolor($target_width,$target_height);
    imagecopy ($target_image, $thumb_image, 0, 0, ($thumb_width - $target_width)/2, ($thumb_height - $target_height)/2, $target_width , $target_height);

    if($filename === FALSE)
    {
      unset($thumb_image);
      return array('file'=>$filename,
                   'width'=>$target_width,
                   'height'=>$target_height,
                   'quality'=>$quality,
                   'type'=>$source_type,
                   'object'=>$target_image
                   );
    }
    else
    {
      imagejpeg($target_image,$filename,$quality);
      unset($target_image,$thumb_image);
      return array('file'=>$filename,
                   'width'=>$target_width,
                   'height'=>$target_height,
                   'quality'=>$quality,
                   'type'=>$source_type
                   );
    }
  }


    function fastimagecopyresampled (&$dst_image, $src_image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h, $quality = 3)
    {
        // Plug-and-Play fastimagecopyresampled function replaces much slower imagecopyresampled.
        // Just include this function and change all "imagecopyresampled" references to "fastimagecopyresampled".
        // Typically from 30 to 60 times faster when reducing high resolution images down to thumbnail size using the default quality setting.
        // Author: Tim Eckel - Date: 12/17/04 - Project: FreeRingers.net - Freely distributable.
        //
        // Optional "quality" parameter (defaults is 3).  Fractional values are allowed, for example 1.5.
        // 1 = Up to 600 times faster.  Poor results, just uses imagecopyresized but removes black edges.
        // 2 = Up to 95 times faster.  Images may appear too sharp, some people may prefer it.
        // 3 = Up to 60 times faster.  Will give high quality smooth results very close to imagecopyresampled.
        // 4 = Up to 25 times faster.  Almost identical to imagecopyresampled for most images.
        // 5 = No speedup.  Just uses imagecopyresampled, highest quality but no advantage over imagecopyresampled.

        if (empty($src_image) || empty($dst_image)) { return false; }
        if ($quality <= 1) {
         $temp = imagecreatetruecolor ($dst_w + 1, $dst_h + 1);
         imagecopyresized ($temp, $src_image, $dst_x, $dst_y, $src_x, $src_y, $dst_w + 1, $dst_h + 1, $src_w, $src_h);
         imagecopyresized ($dst_image, $temp, 0, 0, 0, 0, $dst_w, $dst_h, $dst_w, $dst_h);
         imagedestroy ($temp);
        } elseif ($quality < 5 && (($dst_w * $quality) < $src_w || ($dst_h * $quality) < $src_h)) {
         $tmp_w = $dst_w * $quality;
         $tmp_h = $dst_h * $quality;
         $temp = imagecreatetruecolor ($tmp_w + 1, $tmp_h + 1);
         imagecopyresized ($temp, $src_image, $dst_x * $quality, $dst_y * $quality, $src_x, $src_y, $tmp_w + 1, $tmp_h + 1, $src_w, $src_h);
         imagecopyresampled ($dst_image, $temp, 0, 0, 0, 0, $dst_w, $dst_h, $tmp_w, $tmp_h);
         imagedestroy ($temp);
        } else {
         imagecopyresampled ($dst_image, $src_image, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
        }
        return true;
    }

?>