>>> "Richard" == Richard Stallman <rms@gnu.org> writes:

   > [[[ To any NSA and FBI agents reading my email: please consider    ]]]
   > [[[ whether defending the US Constitution against all enemies,     ]]]
   > [[[ foreign or domestic, requires you to follow Snowden's example. ]]]

   >> For example using gnus the setting

   >> (setq gnus-blocked-images nil)

   > The default value is gnus-block-private-groups, whose doc string
   > says

   >     (defun gnus-block-private-groups (group)
   >       "Allows images in newsgroups to be shown, blocks images in all
   >     other groups."

   > Does that create a vulnerability in some cases?  Can newsgroup
   > postings use an image to determine who reads them?

All I can say: I set the variable to nil, I use chrome with the tracker
email extension, send a message to myself, opening it with emacs/gnus
and the chrome extension software tells me that I have opened it.

If the variable is set as it should be, the tracking software does not
detect that I have opened it.


Slightly off topic, there is software which warns you about tracked
emails or even tries to block them. However that blocking then causes
the tracking software to consider it as opened, although it was not
really opened :-D [1] and which really defeats the whole idea of
tracking, but this is another topic.

Footnotes:
[1]  (I made this experiment  with someone who posses this software)