<?php session_start(); $md5 = md5(microtime() * mktime()); $string = substr($md5,0,5); $captcha = imagecreatefromjpeg("captcha.jpg"); $black = imagecolorallocate($captcha, 0, 0, 0); $line = imagecolorallocate($captcha,233,239,239); imageline($captcha,0,0,39,29,$line); imageline($captcha,40,0,64,29,$line); imagestring($captcha, 5, 20, 10, $string, $black); $_SESSION['key'] = md5($string); header("Content-type: image/jpeg"); imagejpeg($captcha); ?>