I have contacted the forum administration and Andy directly, but I thought I'd mention this here, too, in case someone else has run into the same situation.
There is a size limit on a photo attachment. There always has been so that is nothing new. However, there is now an overall limit on how many attachments a member can post. The forum did not used to have this limitation--- this is something new.
This limit is defined by the total volume one has in attachments on the forum in term of megabytes. A lot of us have been posting photos for many years now, and they are all still there. Which means some of us--- including me--- have reached their total limit. Which means we can no longer attach photos to our posts.
Since there does not seem to be any means of going back and removing past photos from archived posts, this means we are simply locked out of the ability to post photos. And since including photos was one of the major advantages of this forum over things like the e-mail-based T&T list, the inability to post further photos pretty much negates most of the value of the forum, at least in my eyes.
If there is a way to go back and delete photos from archived posts from years back (which may negate the value of those posts for anyone who goes back and reads them), I don't know what it is.
There is a line in the attachments FAQ that refers to this overall attachment limit, so it's not something that my computer is generating on its own. It's a stated limitation of the forum software.
So unless someone comes up with a way for long-time active forum members who use photos to help illustrate their posts to continue using them, I don't see a whole lot of value in the current setup, as much as I like the other aspects of the new format.
I hope it's something that can be addressed in a format or software adjustment. But if it can't I think the forum will be poorer for it. It's a visual world now, and preventing people from taking advantage of the power of visuals is my opinion a sure way to discourage people from participating.