private function getThumbnailsTargetUploadFilepath($key)
    {
        $absoluteThumbnailTargetPath = implode('/', array_filter([
            rtrim($this->results['path'], '/'), (! $this->suffix ? trim($key) : ''),
        ]));

        $this->createDirectoryIfNotExists($absoluteThumbnailTargetPath);

        $resizedBasename = implode('_', [
            $this->results['basename'], $key,
        ]);

        if (! $this->suffix) {
            $resizedBasename = $this->results['basename'];
        }

        $resizedBasename .= '.'.$this->results['original_extension'];

        return implode('/', [$absoluteThumbnailTargetPath, $resizedBasename]);
    }