Very simple chapta idea

<?php

function error() {
        header("Content-Type: text/plain; charset=UTF-8");
        exit(1);
}

header("Content-Type: image/png");

$img = imagecreatetruecolor(0x100, 0x80);
$black = imagecolorallocate($img, 0x00, 0x00, 0x00);
imagefill($img, 0x00, 0x00, $black);
imagestring($img, 4, 0x10, 0x10, "TEST", 0xffffff);

// Striche
// rand(min, max)
$max = rand(2, 8);
for($i = 0; $i < $max; $i++) {
        imageline($img, 0, rand(0, 0x100), 0x100, rand(0, 0x100), 0xffffff);
}

imagepng($img);
imagedestroy($img);

exit(0);

?>