Hi everybody,
Inspired by Khromows howto (Collect visitor stats using any image with the Piwik Tracking API | Living with technology) I tried to follow the instructions but ended up with always getting my own servers IP.
Here’s the steps I made:
I took a fresh installation of the newest piwik.
I created a new site. (ID 2)
I created a new user.
I gave him admin rights for the new site (ID 2).
I noted the new users token.
I downloaded the three files stats_t.php / stats.png and PiwikTracker.php (I pulled this one out of my installation, example.com/analytics/etcetcetc.)
I entered the site ID and the token and the link to my piwik installation into my stats_t.php
I copied those files into the folder on my website /images.
I modified the .htaccess file as mentioned on your site.
But all I get is my servers IP. 
I’ve read through the comments here and tinkered around for almost two days.
I’m adding a justpaste-link to the files I’ve been using.
Any help would be appreciated! I’ve come across other peoples’ posts who were facing the same problems but haven’t found a solution yet.
I don’t know what I’m doing wrong, but I know that I’m moving in circles. 
Thank you for your help and best wishes
Tom