PHP and picture

[istanbul]

<?
 
 $imagekod = '';
 
 for ($i = 0; $i < 8; $i++) {
 
 $imagekod .= chr(mt_rand(100,120));
 $imagekod=strtoupper($imagekod);
 }
// set up image
  $height = 30;
  $width = 100;
  $im = ImageCreate($width, $height);
  $white = ImageColorAllocate ($im, 255, 255, 255);
  $black = ImageColorAllocate ($im, 128, 0, 0);
 
// draw on image
  ImageFill($im, 0, 0, $black);
//  ImageLine($im, 0, 0, $width, $height, $white);
  ImageString($im, 300, 15, 10, $imagekod, $white);
 
// output image
  Header ("Content-type: image/png");
  ImagePng ($im);
 
// clean up
  ImageDestroy($im);
 
?>

Shows different article in every refresh
From my library...