$y1 = $top - $height;
$y2 = $top;
$x1 = 25; //left margin
$x2 = $x1 + $width;

$this->insertLogo($page, $invoice->getStore());

$this->insertLogo($page, $invoice->getStore(),225);//225 is the margin from left

public function insertLogo(&$page, $store = null, $x1 = 25){
        $this->y = $this->y ? $this->y : 815;
        $image = Mage::getStoreConfig('sales/identity/logo', $store);
        if ($image) {
            $image = Mage::getBaseDir('media') . '/sales/store/logo/' . $image;
            if (is_file($image)) {
                $image       = Zend_Pdf_Image::imageWithPath($image);
                $top         = 830; //top border of the page
                $widthLimit  = 270; //half of the page width
                $heightLimit = 270; //assuming the image is not a "skyscraper"
                $width       = $image->getPixelWidth();
                $height      = $image->getPixelHeight();

                //preserving aspect ratio (proportions)
                $ratio = $width / $height;
                if ($ratio > 1 && $width > $widthLimit) {
                    $width  = $widthLimit;
                    $height = $width / $ratio;
                } elseif ($ratio < 1 && $height > $heightLimit) {
                    $height = $heightLimit;
                    $width  = $height * $ratio;
                } elseif ($ratio == 1 && $height > $heightLimit) {
                    $height = $heightLimit;
                    $width  = $widthLimit;
                }

                $y1 = $top - $height;
                $y2 = $top;
                //$x1 = 25; hide this
                $x2 = $x1 + $width;

                //coordinates after transformation are rounded by Zend
                $page->drawImage($image, $x1, $y1, $x2, $y2);

                $this->y = $y1 - 10;
            }
        }
    }