public function isUploadedFile($filePath)
    {
        // If it's a serialized one.
        if (filter_var($filePath, FILTER_VALIDATE_URL)) {
            return true;
        }

        // If it's a normal filename.
        $file = $this->getUploadDir()->getFile($this->getUserDirectoryHash() . '/' . $filePath);
        if ($file->exists()) {
            return true;
        }

        return false;
    }