Missing photo thumbnails

Hello everybody,
after the move to OS5 photo thumbnails don’t show any more in my LG tv as it was usual before.
I already fixed the missing video thumbnails problem installing FFmpeg but thumbnails from photos are still missing.
I explored all possible Twonky tweaks unsuccessfully: I see files but for all of them a generic anonymous thumbnail is displayed.
Thumbnails exist (I see them accessing the Twonky UI from both the pc and MyCloud app) but it looks like they’re NOT transferred to the tv from the MyCloudEX2Ultra.