Plex seems to have changed to using the “Time taken” encoded in the EXIF information of photos as the default sort order and doesn’t seem to offer an easy way to change this. I’m also rather pissed off by this. In fact, if PLEX can’t find that information in the files, it seems to revert to sorting according to the file name (or it might be the file creation date/time, which by the way I did an experiment to see if it was the EXIF data that is causing troubles, corresponds to the file name order).
I don‘t understand we’re is the problem for sort by simple filename? At first it was not allowed to have videos in the picture library. Than it was no problem. But now all the videos an the end of the folder sorted. The system look only for the EXIF entry’s. But the problem videos have no EXIF. Now I use von Synology the DS Photo, there is no problem with sorted by filename. The Plex Pass I canceled.