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);