Captcha

<?php
session_start();
header("Content-type: image/jpeg");

$znak1 = rand(0,9); 
$znak2 = rand(0,9);
$znak3 = rand(0,9);
$znak4 = rand(0,9);
$znak5 = rand(0,9);

$_SESSION['captcha']=$znak1.$znak2.$znak3.$znak4.$znak5;

$podklad = imagecreatefromjpeg("cesta k podkladovemu obrazku");

$farba_textu = imagecolorallocate($podklad, mt_rand(0, 250),mt_rand(0, 250),mt_rand(0, 250));

ImageTTFText($podklad, mt_rand(25,30), mt_rand(-40, 40), 10, 40, $farba_textu, "cesta k fontu/font.tff", $znak1);

$farba_textu = imagecolorallocate($podklad, mt_rand(0, 250),mt_rand(0, 250),mt_rand(0, 250));

ImageTTFText($podklad, mt_rand(25,30), mt_rand(-40, 40), 60, 40, $farba_textu, "cesta k fontu/font.tff", $znak2);

$farba_textu = imagecolorallocate($podklad, mt_rand(0, 250),mt_rand(0, 250),mt_rand(0, 250));

ImageTTFText($podklad, mt_rand(25,30), mt_rand(-40, 40), 100, 40, $farba_textu, "cesta k fontu/font.tff", $znak3);

$farba_textu = imagecolorallocate($podklad, mt_rand(0, 250),mt_rand(0, 250),mt_rand(0, 250));

ImageTTFText($podklad, mt_rand(25,30), mt_rand(-40, 40), 150, 40, $farba_textu, "cesta k fontu/font.tff", $znak4);

$farba_textu = imagecolorallocate($podklad, mt_rand(0, 250),mt_rand(0, 250),mt_rand(0, 250));

ImageTTFText($podklad, mt_rand(25,30), mt_rand(-40, 40), 190, 40, $farba_textu, "cesta k fontu/font.tff", $znak5);

imagecopy($podklad, $podklad, 0, 0, 0, 0, 250, 50);

imagejpeg($podklad);
?>

$farba_textu = imagecolorallocate($podklad, mt_rand(0,
250),mt_rand(0, 250),mt_rand(0, 250));

$farba_textu = imagecolorallocate($podklad, 0,0,0);