This is a really weird one.
Images upload OK. Thumbnails are created OK (they appear in the files directory). But thumbnails appear as broken images in IE (or the alt text in Firefox).
"The dope's got his paths or URLs wrong" I hear you say

Well here's the weird bit. I can check the properties of the thumnail image that's not displaying and the URL is definitely correct. I can right click on the alt text in Firefox and "View Image" and the thumbnail loads in a blank page. Then click the browser back and the thumbnail has magically appeared in the gallery. In IE if I right click the broken thumbnail and "Show Image" it's still broken.... but I can cut and paste the URL from the thumbnail properties into the address bar and the thumbnail loads... click back and it's now displaying in the gallery.
Click refresh in either IE or Firefox and the thumbnail disappears again and I'm back to square one.
This is vbagallery 1.01 on
vB 3.07 by the way.
Cue the Twilight Zone theme...