Have you tried posting in This thread?
There are only two folks on this board who are able to grant access, and one of them, (Ariel) is currently on vacation. The other (Kazuo) has a full time job and a family to take care of, but he will definitely be able to grant you access soon (within the next few days) if you post in that thread.
I realize it's tough to be patient, but if you can hold out a little longer, you'll have posting access soon.
I'm not really sure why you were able to post in the gallery and now you can't post anywhere but here, but it definitely has nothing to do with the size of your photos.