Library thumbnails are saved by post_id (_copy_library_thumb uses
f"{post.id}.jpg") but the library viewer looked them up by file
stem (f"{filepath.stem}.jpg"). For digit-stem files (12345.jpg)
these are the same. For templated files (artist_12345.jpg) the
stem is "artist_12345" which doesn't match the thumbnail named
"12345.jpg" — wrong or missing thumbnails.
Fix: resolve post_id from the filename via
get_library_post_id_by_filename, then look up the thumbnail as
f"{post_id}.jpg". Generated thumbnails (for files without a
cached browse thumbnail) also store by post_id now, so
everything stays consistent.
pax
31089adf7d