Asset Bank should now show icons as the thumbnails for SWF files.
If you want to show a link ‘View Preview’ on the ‘View Asset Details’ page, which when clicked will launch the SWF movie, run the following statement against your Asset Bank database:
UPDATE FileFormat SET CanViewOriginal=1 WHERE Id=400;
Please consider carefully whether you want to enable this functionality as it gives users access to a particular SWF source file without them necessarily having ‘download’ permission on the asset.
If you are running your Asset Bank on Windows, and you want to create thumbnail images for the SWF files in search results, etc. (rather than showing the icon), please read the article on enabling thumbnails for SWF files on Windows