For some unknown reason all thumbnails are lost in my Shotwell, instead all icons are grey. The images themselves are all okay and I can open them all in Shotwell.
There are only empty folders in
.shotwell/thumbs/ so it looks like the thumbnails don't doesn't get generated at all.
I have also tried to re-install Shotwell (by purge it first) without any change.
How do I make Shotwell regenerate all the thumbnails?