A couple of points:<p>- Proton's image proxy is not unique - it's actually how Gmail's images work as well<p>- Removing parameters from URLs would only work if the URL was not a redirect, which most email services do for their users. Also, stripping out URL parameters can also have unintended consequences if a service legitimately relies on them.<p>- Outlook blocks images by default still, which prevents loading the tracking pixel as well.