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