View file guest/image.php

<?php
session_start();
$code =rand(111,999);
$_SESSION['code']=$code;
$im=imageCreateFromPNG("code.png");
$Color = imageColorAllocate($im, 000, 000, 000);
settype ($code, "string");
imageString($im, 7, 15, 3,$code, $Color);
Header("Content-type: image/png");
imagegif($im,"",100);
imageDestroy($im);
?>