I have PWA+PHP pro v0.9.7 on WordPress 3.4.1. (all the latest versions) on my self hosted site.
The images per page feature is not working on any posts or pages. The short codes always show all images in an album, no matter what I set into the plugin options page, or into the shortcode.
For example on this post:
I have the short code:
[pwaplusphp album="Underwater" images_per_page="20" ]
and the images Per Page option at PWA+PHP Plugin Settings is 30, but on the post I get all 400 images. It apparently doesn't matter what numbers I put into images_per_page or whatever album I use, I always get everything from any album.