It’s just a simple Flask server. I parse the user-agent using the user_agents Python library, apply some conditionals upon the result, render the image using Pillow and send it to the user.

This is possible because Lemmy doesn’t proxy external images but instead loads them directly. While not all that bad, this could be used for Spy pixels by nefarious posters and commenters.

Note, that the only thing that I willingly log is the “hit count” visible in the image, and I have no intention to misuse the data.

It appears to have worked