I installed Plogger a couple of days ago, and everything worked fine, until I decided to add some more pictures yesterday. Thumbs do display, but when I click to enter individual images, all I get is a blank square. I've just rolled back to the default layout, assuming that my edits were the causing the problem, but it's still like that. I haven't changed any server settings in the meantime, so this has got me completely stumped... Anyone?
[EDIT] I've removed plogger from my site for now, as I need to have the pictures available more than I need plogger, but I'd definitely like to give plogger another go later
What are your option settings (sign into Plogger admin and click the "Options" tab). Do you have "Generate Indermediate Pictures" unchecked AND "Allow Full Picture Access" unchecked? This results in a blank square being shown on the picture level. You should have at least one of these options checked, otherwise Plogger only has permission / access to the thumbnails, but no larger images.
I'd check this first and if you do have one checked, we can go from there.