I'm getting an error message telling me the forum (not just my thread) has exceeded its attachment limit. The pictures I have is well within the size limit.
I usually PIP using something that's already on the web. If you can put your picture up in whatever online photo album you use or upload to tinypic you can just paste the URL. Have you already tried that and not been able to do it?
Apparently the ProBoards upgrade brought with it an attachment limit, and we are well over the limit. As a result we are going to have to delete old attachments to free up space, meaning you will lose any attachments to older posts so make sure you have them saved elsewhere, such as on Photobucket.
The message you are getting may be a function of the fact that we haven't cleared out enough space yet.