Is there anyway to see a thumbnail in Win 10

[Bsmooth]

I have tried numerous times to use MKVToolnix to have a visable thumbnail for my MKV file for a movie with no results. I stuck to the largest side can only be 600 x 400 but still no thumbnail. I actually wound up making 8 different versions and all of them have just a shot from the movie as a thumbnail. What am I doing wrong ?

[fulldonner]

I have tried numerous times to use MKVToolnix to have a visable thumbnail for my MKV file for a movie with no results. I stuck to the largest side can only be 600 x 400 but still no thumbnail. I actually wound up making 8 different versions and all of them have just a shot from the movie as a thumbnail. What am I doing wrong ?

MKVToolNix does not set custom thumbnails for MKV files that are recognized by media players. Most players generate thumbnails dynamically from the video itself. To embed a custom thumbnail:

Use MKVToolNix: Add a cover image under the "Attachments" tab (JPG or PNG, max 600x400).

Verify the Player: Some players ignore the embedded cover and generate thumbnails from the video. Test with VLC or MPV.

Use an External Tool: Tools like Tag Editor (Windows) or MKVTagEditor might allow you to set a visible cover.