I've been using an image browser for Joomla called ImageBrowser. It's great - easy uploads, easy for clients to use, even handles zip file uploads. I have Joomla v. 1.5.15 installed and the newest version of this plugin as well on 3 or 4 of our sites with no fuss or issues.
Recently, the ImageBrowser on one of our sites started acting strangely. It was as if the Lightbox effect that we should have disappeared completely. I compared the settings for the site to another and found they were identical. I couldn't find a solution in the documentation or forums.
Here's the URL to look at: http://neda.us/photos?view=gallery&folder=BSU+12-5-09. You can compare that to another of our sites with the same plugin and settings at South Oak Floors dot COM. You should be able to click on a thumbnail and get a full size view of the image in a Lightbox.
Any help much needed and much appreciated.