function smart_resize_image( $file, $width = 0, $height = 0, $proportional = false, $output = 'file', $delete_original = true, $use_linux_commands = false )
{
  if ( $height <= 0 && $width <= 0 ) {
   return false;
  }
  $info = getimagesize($file);
  $image = '';
  $final_width = 0;
  $final_height = 0;
  list($width_old, $height_old) = $info;
  if ($proportional) {
   if ($width == 0) $factor = $height/$height_old;
   elseif ($height == 0) $factor = $width/$width_old;
   else $factor = min ( $width / $width_old, $height / $height_old); 
   $final_width = round ($width_old * $factor);
   $final_height = round ($height_old * $factor);
  }
  else {  
   $final_width = ( $width <= 0 ) ? $width_old : $width;
   $final_height = ( $height <= 0 ) ? $height_old : $height;
  }
  switch ($info[2] ) {
   case IMAGETYPE_GIF:
    $image = imagecreatefromgif($file);
   break;
   case IMAGETYPE_JPEG:
    $image = imagecreatefromjpeg($file);
   break;
   case IMAGETYPE_PNG:
    $image = imagecreatefrompng($file);
   break;
   default:
    return false;
  }
  $image_resized = imagecreatetruecolor( $final_width, $final_height );
  if ( ($info[2] == IMAGETYPE_GIF) || ($info[2] == IMAGETYPE_PNG) ) {
   $trnprt_indx = imagecolortransparent($image);
   // If we have a specific transparent color
   if ($trnprt_indx >= 0) {
    // Get the original image's transparent color's RGB values
    $trnprt_color = imagecolorsforindex($image, $trnprt_indx);
    // Allocate the same color in the new image resource
    $trnprt_indx = imagecolorallocate($image_resized, $trnprt_color['red'], $trnprt_color['green'], $trnprt_color['blue']);
    // Completely fill the background of the new image with allocated color.
    imagefill($image_resized, 0, 0, $trnprt_indx);
    // Set the background color for new image to transparent
    imagecolortransparent($image_resized, $trnprt_indx);
   }
   // Always make a transparent background color for PNGs that don't have one allocated already
   elseif ($info[2] == IMAGETYPE_PNG) {
    // Turn off transparency blending (temporarily)
    imagealphablending($image_resized, false);
    // Create a new transparent color for image
    $color = imagecolorallocatealpha($image_resized, 0, 0, 0, 127);
    // Completely fill the background of the new image with allocated color.
    imagefill($image_resized, 0, 0, $color);
    // Restore transparency blending
    imagesavealpha($image_resized, true);
   }
  }
  imagecopyresampled($image_resized, $image, 0, 0, 0, 0, $final_width, $final_height, $width_old, $height_old);
  if ( $delete_original ) {
   if ( $use_linux_commands )
    exec('rm '.$file);
   else
    @unlink($file);
  }
  switch ( strtolower($output) ) {
   case 'browser':
    $mime = image_type_to_mime_type($info[2]);
    header("Content-type: $mime");
    $output = NULL;
   break;
   case 'file':
    $output = $file;
   break;
   case 'return':
    return $image_resized;
   break;
   default:
   break;
  }
  switch ($info[2] ) {
   case IMAGETYPE_GIF:
    imagegif($image_resized, $output);
   break;
   case IMAGETYPE_JPEG:
    imagejpeg($image_resized, $output);
   break;
   case IMAGETYPE_PNG:
    imagepng($image_resized, $output);
   break;
   default:
    return false;
  }
  return true;
}