No more cover art for movies

Hi. Since the last update Plex will no longer find cover art for movies. It does download meta-data (such as short description, etc) but no cover or background art. When I tried a refresh on the whole library, I lost all cover art. I tried deleting the PhotoTranscoder folder but that didn't help either.

DSM 6.0.2-8451 Update 1
Plex (Synology) Version 1.1.3.2700

Any suggestions are welcome.