CCK version 6-x-2.9
imagefield version 6-x-3.11
permissions for your tmp and files directory. 777 and 755, respectively
download method (public or private files) public

I am using Views Gallery to add images (Views Gallery is a module that is "A gallery created using CCK, imagefield, and views."). If I want to edit an image's title after it has already been added to the gallery (ie, appears on the gallery's page), the image thumbnail disappears on the gallery page, and only a blank placeholder is left. Clicking on the image (which brings up the slideshow) also shows no image.

Hovering over the image placeholder in the gallery, I can see that the URL is getting truncated after saving the edited title, as follows:
[mysite]/files/photos/img_0079.jpg becomes [mysite]/files/
The image title below the thumbnail placeholder is changed as desired, and the URL is as expected. Clicking on that link (which goes to the image's View/Edit page) also fails to show the image itself, presumably because of the same URL truncation (although there is no placeholder link for me to hover over and confirm). Likewise, if I make a note of the node URL (ie [mysite]/node/438) the image is still missing from the View/Edit page.

However, the image still exists. If I manually type in the full, untruncated URL (ie [mysite]/files/photos/img_0079.jpg), then the image appears full-screen as expected.

This all happens whether or not I have the "Automatic Alias" option checked or not. It also happens on the Preview page even if a title is not changed (but reverts to the previously saved state). In other words, it appears to be the process of any edit to the image that seems to be the problem.

I've cleared the cache and also disabled all modules that are not required by Views Gallery, including those in optional core, and the problem persists. I'm all out of troubleshooting ideas and I don't know what is the likely culprit: ImageField or something else.