spam.php

<?php
  session_start();

  // generate random number and store in session

  $randomnr = rand(1000, 9999);
  $_SESSION['randomnr2'] = md5($randomnr);

  //generate image
  $im = imagecreatetruecolor(120, 25); // dimensiuni

  //colors:
  $white = imagecolorallocate($im, 255, 255, 255);
  $grey = imagecolorallocate($im, 128, 128, 128);
  $black = imagecolorallocate($im, 0, 0, 0);

  imagefilledrectangle($im, 0, 0, 232, 44, $black);

  //path to font:

  $font = 'arial.ttf';

  //draw text:
  imagettftext($im, 12, -10, 77, 22, $grey, $font, $randomnr);

  imagettftext($im, 12, -6, 66,18, $white, $font, $randomnr);

  // prevent client side  caching
  header("Expires: Wed, 1 Jan 1997 00:00:00 GMT");
  header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
  header("Cache-Control: no-store, no-cache, must-revalidate");
  header("Cache-Control: post-check=0, pre-check=0", false);
  header("Pragma: no-cache");

  //send image to browser
  header ("Content-type: image/gif");
  imagegif($im);
  imagedestroy($im);
?>