How to use Pixel Tracking across domains in PHP

Question

I understand the basics of pixel tracking, I'm able to insert a pixel that references an image on my tracking domain to other websites.

However, how do I increment that actual pixel count on my tracking domain? Is there some kind of log that tells me every time that pixel image was served up? Am i able to do something like:

<img src="http://www.foo.com/serveImage/getImage.php?id=5123" />

then have the getImage page, serve up the image, and increment based on the id that was passed in? or is there a better way to achieve this?

Thank you in advance.

Answer 1

if you want to just output a gif this is a quick simple way, just make sure your script doesn't output anything else before or after:

header("Content-type: image/gif");
header("Content-length: 43");
$fp = fopen("php://output","wb");
fwrite($fp,"GIF89a\x01\x00\x01\x00\x80\x00\x00\xFF\xFF",15);
fwrite($fp,"\xFF\x00\x00\x00\x21\xF9\x04\x01\x00\x00\x00\x00",12);
fwrite($fp,"\x2C\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02",12);
fwrite($fp,"\x44\x01\x00\x3B",4);
fclose($fp);