Image size in forum attachment

$a_images .= display_image_attach($a_data['attach_name'], "100", "100", $data['post_id'])."n";

function display_image_attach($file, $width = 50, $height = 50, $rel = "") {
   $size = @getimagesize(FORUM."attachments/".$file);
      
   if ($size [0] > $height || $size [1] > $width) {
      if ($size [0] < $size [1]) {
         $img_w = round ( ($size [0] * $width) / $size [1] );
         $img_h = $width;
      } elseif ($size [0] > $size [1]) {
         $img_w = $height;
         $img_h = round ( ($size [1] * $height) / $size [0] );
      } else {
         $img_w = $height;
         $img_h = $width;
      }
   } else {
      $img_w = $size [0];
      $img_h = $size [1];
   }