Use phpthumbof in a snippet?

 
$input = "pathtoimage/image.jpg";
$width = 200;
$height = 50;
$options = "w=$width&height=$height&zc=1";   
$thumbnail = $modx->runSnippet("phpthumbof",array('input' => $input, 'options' => $options));

<?php
function getFileList($dir)
  {
    // array to hold return value
    $retval = array();

    // add trailing slash if missing
    if(substr($dir, -1) != "/") $dir .= "/";

    // open pointer to directory and read list of files
    $d = @dir($dir) or die("getFileList: Failed opening directory $dir for reading");
    while(false !== ($entry = $d->read())) {
      // skip hidden files
      if($entry[0] == ".") continue;
      if(is_dir("$dir$entry")) {
        $retval[] = array(
          "name" => "$dir$entry/",
          "type" => filetype("$dir$entry"),
          "size" => 0,
          "lastmod" => filemtime("$dir$entry")
        );
      } elseif(is_readable("$dir$entry")) {
        $retval[] = array(
          "name" => "$dir$entry",
          "type" => mime_content_type("$dir$entry"),
          "size" => filesize("$dir$entry"),
          "lastmod" => filemtime("$dir$entry")
        );
      }
    }
    $d->close();

    return $retval;
  }
  $dirGal = "assets/galeria/".$nomGal;
  $dirlist = getFileList($dirGal);
  echo "<div id='galslide' class='nivoSlider'>";
    foreach($dirlist as $file) {
      if(!preg_match("/\.jpg$/", $file['name'])) continue;
      //    echo "<img src='".$file['name']."'/>";
    $input = $file['name'];
    $width = 50;
    $height = 50;
    $options = "w=$width&height=$height&zc=1";   
    $thumbnail = $modx->runSnippet("phpthumbof",array('input' => $input, 'options' => $options));
    echo "<img src='".$input."' rel='".$thumbnail."'/>";
    }
  echo "</div>";