[NexXxus]

I recently deleted the thumbnails of the background pictures I created beucase I updated some of them but it just won't update it in the thumbnail cache.

So, now every thumbnail is just black after I deleted them.
I tried to set the pictures as wallpapers, but they turn just black.

I tried to regenerate the thumbnails with this option in the picture category but it didn't work.

So. Now how can I update/regenerate it without deleting the whole thumbnail cache?
I don't want to delete the pictures from the movie database -.-

[Martijn]

Delete 'databases/textures.db' from your userfolder.
Should regenerate the thumbnails

[NexXxus]

and what's with the thumbnails in the movie database?
does it regenerate them too?

[Martijn]

It should regenerate every image/thumbnail that was set in the library. There's no real harm done by deleting the textures.db
To be sure you can make a backup of the file.