- Convert never removes a path that is the preview it just wrote. It
compares the device and inode, or the resolved and normcased paths when
the disk has no inode numbers. This covers x_thumb.JPG on a
case-insensitive disk.
- A JPEG XL encode failure re-runs encoder detection only when the
encoder's binary or module is gone. A "no encoder" result is checked
again on the settings read, on a jxl save, and after 60 s, so one slow
probe no longer turns JPEG XL off until a restart.
- The startup sweep now also removes temp files that carry this process's
PID but predate its start. Containers reuse PIDs.
- ffmpeg writes JPEG XL with -update 1, so a % in a file name is never an
image-sequence pattern, and reads videos as file:<path>. The clear and a
startup sweep remove temp files that interrupted writes left behind.
- Convert outdated converts each group of same-stem files once, from the
first source in the R2 order. An old preview that is already gone counts
as removed, and each file's bytes count once. A current preview is only
kept if it decodes.
- An encoder that fails makes the write detect encoders again once. Another
encoder is used if one is found; with none, the file is written as WebP
and the availability Appearance shows is refreshed.
- Changing the thumbnail format, quality or size while Convert outdated runs
returns 409 busy. If the format still changes underneath, the job stops
without removing anything.
- Legacy preview spellings are matched case-insensitively, so X_thumb.JPG
counts as outdated.
- History's cover uses the same lookup as Images. It serves .jxl only when
Accept lists image/jxl, and otherwise the original or the placeholder.
- A video whose thumbnail the browser cannot show keeps its own element
(Images) or its label (Library).
Automatic previews (capture and first view), the thumbnail job, the
legacy gallery routes and the history route write <stem>_thumb.webp
(or .jxl/.jpg) with the configured quality and size limit, for images
and videos alike: video frames, ffmpeg's included (a PNG on stdout,
never upscaled), and the placeholder are encoded like images.
Listings, duplicates, enrichment, the autotag scan and the history
route show any preview the file owns, the current format first, so
older _thumb.png previews keep working until converted. A request for
an older name answers the current preview. Previews are served with
an explicit image/webp or image/jxl type and the same cache headers.
The plan and status count missing, outdated (another format) and
ready previews; the missing job never writes beside an outdated one.
Removing a file removes its previews in every format; the clear
removes .webp and .jxl too. Encoder processes are killed at shutdown.
A preview is only a placeholder: inspection refuses paths under
thumbnails/ and always reads the original, and the inspector cover
accepts the listing's preview in any format the file owns.
Thumbnail format (webp default, jxl, jpeg), quality (1-100, default 80)
and size limit (128-2048 px, default 512) are server settings in the
config.json thumbnails section, saved with the settings revision. The
never-read gallery thumbnail_size is gone: older saves wrote its unused
default 256 into config.json.
One module names previews (<stem>_thumb.webp/.jxl/.jpg) and finds the
preview a source owns, preferring the configured format; legacy names
are still found. The encoder module writes every preview atomically and
verifies it decodes. JPEG XL needs no new dependency: Pillow (natively
or with pillow_jxl), ffmpeg with libjxl, or cjxl; without one the
settings refuse jxl (400 jxl-unavailable) and GET says why. Encoder
processes are tracked, bounded and killed at shutdown.
Vito Sansevero