Only if you click ALWAYS do this for this sender. This is how it works, not a bug.

You can read about it here. http://kb.mozillazine.org/Privacy_basics_%28Thunderbird%29

Of course I always want it to display graphics. That has nothing to do with making it a Contact. I said bug but it means error in concept.

The next version will as I understand it remove this as a prelude to the new address book, which will not be using the address book as a white list for remote graphics.

That's good. Mozilla said they were not continuing to develop Thunderbird. Are they continuing to adapt it to W8? The specs did not say it was for W8 but it does work. Many more people should know about this program.

Shows windows 8 in the system requirements... see https://www.mozilla.org/en-US/thunderbird/24.0/system-requirements/

Your correct, Mozilla are only contributing stability and security fixes and build support to Thunderbird. But there is a fairly vibrant volunteer network and that includes developers Some of whom work for Mozilla incidentally. While the pace of change has slowed I do not think that is a bad thing. Most people appeared about sick of 6 weekly updates anyway.

But at the moment the future is bright, as long as there are people who want a mail client that is. Web mail is taking over and not necessarily;y in a good way as the big vendors try and build walled gardens that lock you into their brand.