header('Content-Type: image/jpeg');
$num = range(100, 999);
$first = mt_rand(0,898);
$second = mt_rand(0,898);
$len = 86;
$size = 8;
$sum = $num[$first] + $num[$second];
$img = $num[$first] . ' + ' . $num[$second];
$im = imagecreatetruecolor($len, 20);
$text_color = imagecolorallocate($im, 255, 255, 255);
imagestring($im, 5, 4, 2, $img, $text_color);
imagejpeg($im);