Chris is right, I think it's 15 but not sure about that.
I also have a problem sometimes, where they don't show in the "draft" post, but after submitting it, they are there. No big deal to bother Cris with, but it's a bit annoying not being able to manage photo uploads easily.
Cris put a lot of time and effort into reviewing and revising the upload procedure, (thanks for the effort Cris) but on my iPad, life is worse after the "improvements".
No complaint here Cris, if you see this, just an observation.