<?php

  header("content-type:image/jpg");

  $src ="image/t3.jpg";

  $info = getimagesize($src);

  $type = image_type_to_extension($info[2],false);

  $fun = "imagecreatefrom{$type}";

  $image = $fun($src);

  $imagemark = "image/t1.jpg";

  $info2 = getimagesize($imagemark);

  $type2 = image_type_to_extension($info2[2],false);

  $fun2 = "imagecreatefrom{$type2}";

  $water = $fun2($imagemark);

  imagecopymerge($image,$water,20,30,0,0,$info2[2],$info2[1],30);

  header("Content-type:".$info['mine']);

  $func="image{$type}";

  $func($image);

  imagedestroy($water); 

?>