private function _generateIco(OutputInterface $output)
    {
        $filename = $this->_outputFolder . "favicon.ico";
        $output->writeln("Creating: <info>{$filename}</info>");


        $originalImage = $this->_imagine->open($this->_inputFile)->strip();
        $originalImage->copy()
                ->resize(new \Imagine\Image\Box(16, 16))
                ->save('tmp-16.bmp');

        $icon = $this->_imagine->open('tmp-16.bmp');
        $icon->layers()
                ->add($originalImage->copy()->resize(new \Imagine\Image\Box(32, 32)));

        if ($this->_use48Icon)
        {
            $icon->layers()->add($originalImage->copy()->resize(new \Imagine\Image\Box(48, 48)));
        }
        if ($this->_use64Icon)
        {
            $icon->layers()->add($originalImage->copy()->resize(new \Imagine\Image\Box(64, 64)));
        }

        $icon->save($filename, array(
            'flatten' => false
        ));

        unlink('tmp-16.bmp');
        return true;
    }