Number of posts per page

I thought it typically displays 40 posts per page but then I saw one thread with just 10 posts a page. Is this number defined by the OP of the thread? Sometimes when a thread is picture heavy it takes lots of time to load and scroll down. I'd like to know how to break it down into more pages if possible. Thanks.

Moderators (Gardeners and Stewards) have the ability to fiddle with the amount of posts per page, with a special set of buttons that we have.

This isn't a power that the OP (or any non-moderator) has, but if they notice that a thread is really picture-heavy and is hard to load, they can hit the report button and ask for the amount of posts per-page to be modified.

I hope that helps!