public function opacity(&$image, $opacity)
    {

        if ($image->isAnimated()) { // Ignore animated GIF for now
            return $this;
        }

        // Bounds checks
        $opacity = ($opacity > 1) ? 1 : $opacity;
        $opacity = ($opacity < 0) ? 0 : $opacity;

        $image->getCore()->setImageOpacity($opacity);

        return $this;
    }