Right now, because thumbs are all kept in the same folder, Plogger may not yet be suitable for 5000+ image galleries. Filesystems take a much greater performance hit than we expected.
Searching the forum will likely yield the relevant thread.
Hmm....after a few hours of hacking almost the entire codebase with little success, I think I'll go an alternate route. The upgrade path would be miserable if I did successfully re-engineer to support another layer.
Instead, I'll just create multiple plogger instances, and have an interface that allows entrance to all any of them. Sound reasonable?
So, on my 'gallery entry' page, I'll have links to:
plogger1/ plogger2/ plogger3/ plogger4
That will give me the depth I need. Granted, it'll create 4 management interfaces, but I think I can tweak the cookies to have one login access all 4 galleries.