There is no limit that I am aware of, personally, I have over 2900 pictures posted on the iboats forums. You are limited to the number of pictures per post. 5 I believe is the number. In that case, just post that particular post, then do a reply to that post and add 5 more.
No, unfortunately that's not working. I am trying to post a sample picture here in this note and it won't let me. I get a messages that says "you have exceeded your quota by 57.3k". Any other forum support sources I could ask?