Hi,
for our upcoming release, we've added some more formats to be recognized as image, so there'll be a thumbnail/preview:
- TIFF
- PSD
- PS / EPS
- PDF / AI
- WEBP
Sorry that we cannot allow all formats supported by IM, since we need some internal classification and mapping information to handle different files and file extensions the right way.
Hopefully we now support the most common image formats. If there's something missing, just let us know!