Explorer thumbnails

EMPF Preview includes a Windows thumbnail provider for .empf files.

How it works

When Windows Explorer needs a thumbnail, it asks the EMPF Preview thumbnail provider to render a preview image. EMPF Preview renders a preview and Windows caches it.

Why thumbnails sometimes appear slowly

Windows caches thumbnails aggressively. If Windows already cached a generic icon, it may not request a new thumbnail immediately.

How to refresh

1. Close and reopen the folder.
2. Switch to Large icons.
3. Copy the .empf file to a new local folder.
4. Reinstall or run the thumbnail refresh tool if available.

OneDrive note

Files stored in OneDrive with Files On-Demand may behave differently because they can be cloud-backed reparse points. For reliable thumbnails, test with a normal local folder or files marked as always available offline.

Render size

The Explorer thumbnail provider renders up to 1024 px, balancing clarity with Explorer cache performance.