I am using Jellyfin also to organize, browse and view my photos, what was working pretty well until the latest update to 10.5.5 (on Ubuntu 18.0.4).
Now photos are not displayed anymore. Only the directory structure is displayed and some videos I took with my camera and stored next to the photos.
I deleted the photos library and created it anew. I noticed that a couple of photos are displayed shortly after scanning starts but disappear after a while.
Could you please look into this issue?
Thank you very much.