PhpOffice\PhpPresentation\Shape\Drawing\ZipFile::getIndexedFilename PHP Method

    public function getIndexedFilename()
    {
        $output = pathinfo($this->getZipFileIn(), PATHINFO_FILENAME);
        $output = str_replace('.' . $this->getExtension(), '', $output);
        $output .= $this->getImageIndex();
        $output .= '.' . $this->getExtension();
        $output = str_replace(' ', '_', $output);
        return $output;
    }