if($this->m_img->m_gih->m_bLocalClr) {
      $nColors = $this->m_img->m_gih->m_nTableSize;
      $rgbq    = $this->m_img->m_gih->m_colorTable->toRGBQuad();
      if($bgColor != -1) {
        $bgColor = $this->m_img->m_gih->m_colorTable->colorIndex($bgColor);