Learn how to use ImageMagick to have Index Manager create thumbnails and previews of image formats not natively supported.
First download ImageMagick from their website (external link). You will need the 64 bit Windows version with 8-bit processing. The Portable version (delivered as a zip file) works well without requiring installation.
Navigate to the Index Manager program folder (typically in C:\Program Files\FotoWare\Index Manager 8.0) and create a new subfolder called ExternalConverter.
Copy the entire contents of the ImageMagick zip file to the ExternalConverter folder and restart the Index Manager service.
How it works
Index Manager will now call upon ImageMagick to create thumbnails and previews of image formats it does not natively recognize.