Zoombrowser 3.3.2.39 ReadMe file says "There are many variations to the TIFF formats and ZoomBrowser EX may not handle all of them. When such an image file is imported, ZoomBrowser EX will replace the thumbnail with the file extension (e.g. ".TIF")."
Only mine doesn't do this. If I save a TIF with LZW compression, as far as Zoombrowser is concerned there is no sign of its existence at all. I found this very confusing, especially as I'd forgotten that I'd saved some TIFs with LZW compression and others straight, until I worked out what was happening.
Do others running Zoombrowser find the same problem? I really think Canon should put something in the Help file. All that says is that TIF files are supported, full stop.

