Hi Ian, do you mean in email messages?

A tracking pixel is a tiny image with a URL that has tracking parameters, like https://www.trackingserver.com/?userid=xyyzz1234

When Firefox connects to the server to retrieve the image, the server receives that userid parameter as part of the request and logs it for later reference. The server may send back some cookies that Firefox will share on future requests for files from the same server. In the case of basic email tracking, it doesn't need to send cookies because it already knows you read the message based on the image request. This is why email sites tend to block images by default and let you decide whether to retrieve them.

Some tracking servers are blocked by Firefox's built-in Enhanced Tracking Protection feature, but I'm sure new ones are popping up all the time.

Firefox doesn't have a specific filter for tiny images, as far as I know, or a way to strip off suspicious parameters from image URLs. Those would be interesting features.

Hello,

Thanks for the super quick reply. It is tracker pixels within email. I use em client hi-lites that one is present and as previously mentioned if I upgrade blocking. Was I correct in thinking that if I dont download pictures. logo which Em client doesnt by default the tracking wont be activated? If activated are they activated for life or just per session?

Tracking Protection set to Strict will block tracking content like tracking pixels and installing uBlock Origin will block more with the privacy filters enabled. The email client may still mark them as existing even though you are successfully blocking them at your end.

Thanks for the super quick reply. It is tracker pixels within email. I use em client hi-lites that one is present and as previously mentioned if I upgrade blocking. Was I correct in thinking that if I dont download pictures. logo which Em client doesnt by default the tracking wont be activated? If activated are they activated for life or just per session?

If you don't let pictures load in the message, then normally your browser or other email client doesn't request the image from the server and the server will not get the signal that you read the message.

Regarding "for life" or "just per session":

If the server sets a cookie when sending the image, and if you open another email message with a tracking image from the same server, then the browser or other email client will send that server the cookies it previously set. How long those cookies persist depends on your browser settings.

Thanks all. That's made it clear. super quick help.

Take care