$image1 = GD::Image->newFromGif($file1); 
$image2 = GD::Image->newFromGif($file2);
$image3 = new GD::Image (20, 10);

#$image->copy($sourceImage,$dstX,$dstY, $srcX,$srcY,$width,$height)
$image3->copy($image1,0,0,0,0,10,10);
$image3->copy($image2,20,0,0,0,10,10);