I feel silly. Well, of course the full image didn't open using Thickbox: the Default theme (which I use in my customized theme) uses the script only to display the image's [i]metadata[/i], and not the full version of the image.
I think I found the place where I must insert it. [b](NOTE: the forum kept deleting parts of the code, so I susbstituted < > with [ ]... sorry if that makes it harder to read):
`
[?php
$fullimage = getFullImageURL();
if (!empty($fullimage)) {
?]
[a href="[?php echo htmlspecialchars($fullimage);?]" title="[?php echo getBareImageTitle();?]"]
`
I placed class="thickbox" here:
`
[a href="[?php echo htmlspecialchars($fullimage);?]" title="[?php echo getBareImageTitle();?]" class="thickbox"]
`
And sure enough, thickbox is called, the overlay appears and [i]something[/i] appears, only it's not the image. Thickbox apparently doesn't like the link that's being passed to it (for instance, [/b][b]/cboy/zenphoto/zp-core/full-image.php?a=laborers&i=78630169.jpg&q=75[/b], instead of the actual URL to the image), and all I get is a long string of gobbledygook.
I managed to get this far, but I'll probably need help with the rest since I'm not exactly a PHP guru. How can I get Zenphoto to echo the actual url of the full-sized image so that TB can display it?
Regards,
Ed