When I set the images/page option under a theme and then click save, it reverts back to the old quantity. Is there somewhere else in admin that might be overriding this?

What version of Zenphoto?

I figured this out. I needed to click on each album, (upper right corner of edit theme), and set it that way album by album

Then you must have assigned themes to your albums. Each album/theme has the ability to have different settings. Maybe you did not intend this and want only one theme. Then remove all the "album" themes.