TIF should be one of the @movieexts for compatibility with Internet Explorer, Firefox and Mozilla instead of @imgexts.
With TIF in @imgexts I get the old blank box. But, If I put TIF in @movieexts, it will open a separate browser window or tab and invoke the Quicktime or other designated TIF file viewer (on my windows machine, QT is the default viewer for TIF)
Tested this on WIndows with IE, Mozilla and Firefox, on Linux with Firefox.
When I tested Konkeror on Linux, the browser was able to handle the TIF extension internally as another image type (TIF in @imgexts), but demanded a plugin when I put the TIF in @movieexts