Need a quick and dirty captcha?
session_start();
$str = str_shuffle(‘abcdefghijklmnopqrstuvwxyz0123456789′);
$substr = substr($str, 0, 6);
$im = imagecreate(60, 25);
// white background and blue text
$bg = imagecolorallocate($im, 255, 255, 255);
$textcolor = imagecolorallocate($im, 0, 0, 0);
// write the string at the top left
imagestring($im, 5, 2, 4, $substr, $textcolor);
// output the image
header(“Content-type: image/png”);
imagepng($im);
Should give you a simple image (but easily decipherable by OCR Readers )