Picture upload Problem

Hello forum members,

I have a short question. I am using QubesOS 4.1. If I now upload an image (from the same Qube) somewhere from Librewolf or Firefox, such as Ebay-Kleinanzeige.de, then only a gray image can be seen. I have already seen the problem with several portals. Does anyone have the same problems or does anyone know what’s causing it? It shouldn’t really be due to the hard disk encryption.

Best regards

Are you using arkenfox user.js by any chance?

Yeah you’ve probably turned on privacy.resistFingerprinting, and the website implements uploading by extracting canvas image data:

2020-04-24-10-28-54-496d8e