movePreviewImage example

$directory = $this->getThemeDirectory($data['template']);
        $this->generateStructure(
            $this->structure,
            $directory
        );

        $this->eventManager->notify('Theme_Generator_Structure_Generated', [
            'data' => $data,
            'directory' => $directory,
        ]);

        $this->movePreviewImage(
            $this->getThemeDirectory($data['template'])
        );
    }

    /** * @param string $directory */
    private function movePreviewImage($directory)
    {
        $this->fileSystem->copy(
            __DIR__ . '/preview.png',