Picture of a plane and a question about Mozilla Thunderbird

I've installed Mozilla Thunderbird and am having no problems reading the
posts to this newsgroup.

When I was using Outlook Express I could go to Tools - Options -
Maintenance - Clean up now to delete all of the headers and messages
that had built up in each newsgroup. It freed up space on my hard drive.

How can I do the same thing in Thunderbird? I can't find the equivalent
actions.

In the meantime, the aircraft shown is a guy named Eric, no further
ident so far, flying in the back seat of Blue Angel F/A-18 tail number 7
during a practice airshow here last Tuesday. The chase plane was always
in the best place to get the best shot. Maybe if Eric reads this post
he will contact me and let me know where he posts his images.....

Regards from Pensacola (went to the beach yesterday...it was warm and
the water was okay but too rough to swim....surfers were out...we
collected shells and created more work for our dermatologist), Tom