Adding user picture to discuss profiles

<?php
//LINE 13 IS IMPORTANT - PATH WHERE THE AVATARS ARE SAVED
//LINE 41 IS IMPORTANT - FILE NAME
// initialize output;
$output = true;
// get the current user name to for dicroty placement
$userName = $modx->user->get('username');
 
// valid extensions
$ext_array = array('jpg', 'jpeg', 'gif', 'png');
 
// create unique path for this form submission
$uploadpath = 'assets/userfiles/' . $userName .'/';
 
// get full path to unique folder
$target_path = $modx->config['base_path'] . $uploadpath;
 
// get uploaded file names:
$submittedfiles = array_keys($_FILES);
 
 
//get exsisting user profile data for Profile_Photos
$fields = $modx->user->getOne('Profile')->get('extended');
$Photo_fields = $fields['Profile_Photos'];
 
// loop through files
foreach ($submittedfiles as $sf) {
 
  // Get Filename and make sure its good.
  $filename = basename( $_FILES[$sf]['name'] );
 
  // Get file's extension
  $ext = pathinfo($filename, PATHINFO_EXTENSION);
  $ext = mb_strtolower($ext); // case insensitive
 
  if($filename != '') {
    $modx->log(modX::LOG_LEVEL_ERROR,'in file name loop'.$filename);
                    // is this the right type of file?
    if(in_array($ext, $ext_array)) {
      //create file called the filename that has been sanitized
      //$filename = strtolower(preg_replace("/[^A-Za-z0-9.]+/i", "-", $filename));
      //$filename = $filename . '.'.$ext  ;
      $filename = avatar . '.'.gif  ; //replaced $filename . '.'.$ext with avatar .gif because of avatar_url chunk;
 
 
      // full path to new file
      $myTarget = $target_path . $filename;
 
      // create directory to move file into if it doesn't exist
      mkdir($target_path, 0755, true);
      if(file_exists($myTarget)) {
        chmod($myTarget,0755); //Change the file permissions if allowed
        unlink($myTarget); //remove the file
      }
 
      // is the file moved to the proper folder successfully?
      if(move_uploaded_file($_FILES[$sf]['tmp_name'], $myTarget)) {
        // set a new placeholder with the new full path (if you need it in subsequent hooks)
        $hook->setValue($sf, $uploadpath . $filename);
        // set the permissions on the file
        if (!chmod($myTarget, 0644)) { /*some debug function*/ }  
      } 
      else {
        // File not uploaded
        $errorMsg = 'There was a problem uploading the file.';
        $hook->addError($sf, $errorMsg);
        $output = false; // generate submission error
      }
    } 
    else {
      // File type not allowed
      $errorMsg = 'Type of file not allowed.';
      $hook->addError($sf, $errorMsg);
      $output = false; // generate submission error
    }
  } 
  else {
    //check to see if there is exsisting photofields value and return value if so
    if ($Photo_fields != '')
    {
      $hook->setValue($sf, $Photo_fields);
       
    }
    else{       
      // if no file, don't error, but return blank
      // is the file name empty (no file uploaded) and exsiting photofields empty
      $hook->setValue($sf, '');
    }
  }
}
return $output;