Image/Barcode

Hi.... I want to add the value return by   require_once 'Image/Barcode.php'; Image_Barcode::draw($string, "code128", "gif");   to a variable and can see his value as image jpg, png or gif.   I try use some like this   <?php header("Content-Type: image/png"); $im = @imagecreate(110, 20)     or die("Cannot Initialize new GD image stream"); $color_fondo = imagecolorallocate($im, 0, 0, 0); $color_texto = imagecolorallocate($im, 233, 14, 91); imagestring($im, 1, 5, 5,  "A Simple Text String", $color_texto); imagepng($im); imagedestroy($im); ?>   to can add the image of the codebar in the variable $im by replacing the text "A simple text string" by the value return by draw(), but I can´t do it... This is ok?   Thanks.... best regards   Alejandro