How to Create a dynamic signature using the GD Library in PHP?

<?php
header ("Content-type: image/png");
$background = imagecreatefrompng("gdimg.png");
$white = imagecolorallocate($background, 255, 255, 255);
imagettftext($background,9,0,10,18,$white,"verdana.ttf","My Name is: Pugalenthi Manian");
imagettftext($background,9,0,10,33,$white,"verdana.ttf","Current Location: Hyderabad");
imagepng ($background);
?>