Confused about closed threads

[Silk]

Hi, I'm new but I post a lot in the Heritage & History forum as that's my area of special interest.

But I have a question please. I've found a few very interesting threads that relate to stuff I post on/have an interest in and would love to add a comment/post in the thread but I'm unable to due to the threads being closed (and I hate to post a duplicate thread.) Is there a policy that threads have to be closed after a certain time? I'm just confused why so many are closed. Some of the subjects are great ones!

(P.S. I did message two authors of the posts so far asking if they could please ask to reopen them but I'm not sure how often they come on.)

Silk

P.S. I was just going to post a question regarding the picture posting (to do with why they display as so tiny) but it's closed too so I can't add a further question. Could someone explain that as well... I know the pics come up as a bit bigger when you click on them but they still aren't very big. I did read the picture posting sticky and understand about the way to post a pic already but didn't see an explanation as to the size problem.