AvatarModel::isAvatarFolderWritable PHP Method

    public static function isAvatarFolderWritable()
    {
        if (is_dir(Config::get('PATH_AVATARS')) and is_writable(Config::get('PATH_AVATARS'))) {
            return true;
        }
        Session::add('feedback_negative', Text::get('FEEDBACK_AVATAR_FOLDER_DOES_NOT_EXIST_OR_NOT_WRITABLE'));
        return false;
    }

 /**
  * Create an avatar picture (and checks all necessary things too)
  * TODO decouple
  * TODO total rebuild
  */
 public static function createAvatar()
 {
     // check avatar folder writing rights, check if upload fits all rules
     if (AvatarModel::isAvatarFolderWritable() and AvatarModel::validateImageFile()) {
         // create a jpg file in the avatar folder, write marker to database
         $target_file_path = Config::get('PATH_AVATARS') . Session::get('user_id');
         AvatarModel::resizeAvatarImage($_FILES['avatar_file']['tmp_name'], $target_file_path, Config::get('AVATAR_SIZE'), Config::get('AVATAR_SIZE'), Config::get('AVATAR_JPEG_QUALITY'));
         AvatarModel::writeAvatarToDatabase(Session::get('user_id'));
         Session::set('user_avatar_file', AvatarModel::getPublicUserAvatarFilePathByUserId(Session::get('user_id')));
         Session::add('feedback_positive', Text::get('FEEDBACK_AVATAR_UPLOAD_SUCCESSFUL'));
     }
 }