<?php
header("Content-Type: image/png");
session_start();
$width = 150;
$height = 40;
$stringlen = 5;
if ($stringlen > 32){
	$stringlen = 32;
}
$stringsize = intval($height/2);
$randomsize = intval($stringsize * mt_rand(90,110) * .01);
$im = imagecreate($width, $height); 
$chunksize = $width / $stringlen;
$xmax = intval($chunksize * $i + $chunksize) - $rightx;
$xmin = intval($chunksize * $i) - $leftx;
$ymax = intval($height) - $topy;
$ymin = intval($randomsize) - $bottomy;
$randx = mt_rand($xmin, $xmax);
$randy = mt_rand($ymin, $ymax);
$white = imagecolorallocate($im, 255, 255, 255);
$color = imagecolorallocate($im, 192, 192, 192);
$black = imagecolorallocate($im, 0, 0, 0);
$string = md5(mt_rand(0,9999)); 
$new_string = strtoupper(substr($string, mt_rand(0, 32-$stringlen), $stringlen));
$_SESSION['image_verify_string'] = $new_string;
imagefill($im, 0, 0, $black);
$fnt = imageloadfont("batik.gdf");
imagestring($im,$fnt,50,$stringsize-8,$new_string,$white);
for ($i = 0; $i < mt_rand(100,200); $i++) {
	imagesetpixel($im, mt_rand(0,$width), mt_rand(0,$height), $white);
}
for ($i = 0; $i < mt_rand(5,15); $i++) {
  $rand_x = mt_rand(0,$width);
  $rand_y = mt_rand(0,$height);
  if(mt_rand(0,1) < 0.5) $sign1 = -1;
  else $sign1 = 1;
  if(mt_rand(0,1) < 0.5) $sign2 = -1;
  else $sign2 = 1;
  imageline($im, $rand_x, $rand_y, $rand_x + $sign1*mt_rand(5,30), $rand_y + $sign2*mt_rand(5,30), $white);
}
imagepng($im);
imagedestroy($im); 
?>