Refreshing thumbnails

I did the Power Cycle. Still the wdtv keeps showing the old images.

The films are on a hard disk connected to the wdtv by usb. I had already cleared the library and deactivated it. Then I reactivated the media library: nothing changes.

This is the structure:

I have the problem with this persistence of old thumbnails in the grid view. Every time I have deleted the .wdtv folder. Thus I’m not replacing the thumbs created by the WDTV but rather changing the movie.jpg (in this case the Abel.Gance.1941.Vénus.aveugle.jpg ). If I change the movie and image name just adding a word, the thumbnails is always the same. If I change completely the name to aaazzz.avi and aaazzz.jpg, only then it shows the new image.

I’ve read in old messages in the forum that the wdtv stores thumbnails in a tmp\cache folder?