When I'm in the admin section, I can upload images, name them, pick their crop, arrange them, anything I want, no problems. I can also see them appearing in mySQL and the info appears correct to me.

However, when I go to 'view album' and look to see what my site will look like to visitors, there's nothing. The albums are there, but they all appear empty. I've checked and double checked that all my images are set to 'visible'. I'm not receiving any errors anywhere, as far as I can tell, it just doesn't show my images. I've spent the last three hours installing and reinstalling, and same issue every time.

Has anyone encountered this before? If so, what did you do? Any hints would be greatly appreciated!

Are your albums set to published?

Yes. The 'manage content publication' page also confirms that "no albums are unpublished"

Actually this appears to be the tip of the ice berg, I'm discovering that reloading my site causes all the thumbnail info to be dropped from the mysql tables. That is, if I change the thumbnail crop in the admin end, I can see the change in the icons back there and also see the values change in my sql database. I can move around the admin area no problem. But the moment I reload index.php or any other part of my gallery, the sql tables change all the crop data back to null... And it still shows all my galleries as empty. This happens with all of the included themes plus several that I downloaded.

This is beyond bizarre and I don't even know where to begin to puzzle over this.

Actually, scratch that, it isn't forgetting the crop information. It turns out that when I view my gallery it's completely emptying my sql zp_images table. No more records. No wonder it thinks the galleries are empty. Then when I go back to the admin section, it appears to scan the album folders and re-create the images in the table. I can see the ID #s of the images creep upwards every time I reload.

So the new question is, why are my tables being dumped when I view the gallery? o.O

I have no idea, we never encountered this ourselves nor did we ever get any report about this. Besides, please look at your server's error log and also tell us the Zenphoto version used. If this is not 1.3 you need to upgrade.