function insert_watermark($min_image) {
        global $config;
        $margin = '100%';
        
        $this->watermark_image_light = ROOT_DIR . '/templates/' . $config['skin'] . '/dleimages/watermark_light.png';
        $this->watermark_image_dark = ROOT_DIR . '/templates/' . $config['skin'] . '/dleimages/watermark_dark.png';
        
        $image_width = imagesx( $this->img['src'] );
        $image_height = imagesy( $this->img['src'] );
        
        list ( $watermark_width, $watermark_height ) = getimagesize( $this->watermark_image_light );
        
        $watermark_x = $image_width - $margin - $watermark_width - '100%';
        $watermark_y = $image_height - $margin - $watermark_height + '100%';
        
        $watermark_x2 = $watermark_x + $watermark_width;
        $watermark_y2 = $watermark_y + $watermark_height;
        
        if( $watermark_x < 0 or $watermark_y < 0 or $watermark_x2 > $image_width or $watermark_y2 > $image_height or $image_width < $min_image or $image_height < $min_image ) {
            return;
        }
        
        $test = imagecreatetruecolor( 1, 1 );
        imagecopyresampled( $test, $this->img['src'], 0, 0, $watermark_x, $watermark_y, 1, 1, $watermark_width, $watermark_height );
        $rgb = imagecolorat( $test, 0, 0 );
        
        $r = ($rgb >> 16) & 0xFF;
        $g = ($rgb >> 8) & 0xFF;
        $b = $rgb & 0xFF;
        
        $max = min( $r, $g, $b );
        $min = max( $r, $g, $b );
        $lightness = ( double ) (($max + $min) / 510.0);
        imagedestroy( $test );
        
        $watermark_image = ($lightness < 0.5) ? $this->watermark_image_light : $this->watermark_image_dark;
        
        $watermark = imagecreatefrompng( $watermark_image );
        
        imagealphablending( $this->img['src'], TRUE );
        imagealphablending( $watermark, TRUE );
        
        imagecopy( $this->img['src'], $watermark, $watermark_x, $watermark_y, 0, 0, $watermark_width, $watermark_height );
        
        imagedestroy( $watermark );
    
    }