I have downloaded and implemented plogger here, www.tdako.com/plogger and I tweaked it a bit. Just a bit. What I'd like to do now is one of two things:
1) Make the comments in such a way that they open into a small pop-up window. The chances here are that if a viewer has a pop-up blocker, the comment window might get blocked
or
2) Use something similar to Show/Hide Details underneath each picture. So there a link that would open the comments inline or the fields to add the comments.
I've seen it before on other sites, but I don't know if it is possible here.
1) Yes, it's most likely you'll get caught with popup blockers, so I think doing something in the page with javascript is easiest. Just make sure whatever you do with show/hiding that initially it's hidden by the javascript, not the markup, so that if javascript is disabled it won't be hidden initially (and could therefore not be seen).
2) I did precisely this, and it's very simple. Copy the functions in dynamics.js in your Plogger directory, and rename them to showComments() and hideComments() -- there are a few changes in the functions you'll have to make; then if you make all of the necessary changes in gallery.php (including adding show/hide comments text similar to the EXIF toggle).
I have it in my own gallery.php/dynamics.js, and would be happy to share (it works), but don't know how much else I've edited and what else it would break.