Phone photos store landscape pixels plus an EXIF orientation tag. Browsers honour
the tag for <img>, but Pillow (our thumbnails) and many vision-model image
decoders do not — so the thumbnail rendered rotated AND the model literally
perceived the photo sideways (noticed earlier as model "hallucinations", before
thumbnails made the rotation visible).
Normalize on read, at both surfaces:
- new core/images.normalize_image_orientation: bakes the rotation into the pixels
and re-encodes (preserving format); images with no / identity orientation pass
through untouched (pristine original, no per-send cost).
- make_thumbnail applies exif_transpose — after the decompression-bomb pixel gate,
which now also covers the transpose decode.
- attachment_to_content_part runs image bytes through the normalizer before
base64, so the primary model and the perception model both get upright pixels.
Because normalization is on read (not at upload), it fixes already-stored uploads
too.
- TextDecoder in the text-preview stream now flushes on completion/cancel, so a multibyte UTF-8 char split across a chunk boundary isn't dropped (Copilot).
- send() clears self._wire_part_cache in a finally so the per-send memo (which can hold large rasterized PDF page-images) is released at send end instead of retained on an idle session until the next send (Copilot + fix-review).
- Make the implicit byte-string concatenation in _minimal_pdf explicit (+) in test_pdf.py and test_thumbnails.py so it can't read as a missing comma (CodeQL / github-code-quality).
make_thumbnail set Image.MAX_IMAGE_PIXELS=40M, but Pillow only raises DecompressionBombError above 2x the cap; a 40-80M px image merely warns and decodes fully (~480MB RGB), defeating the documented bound.
Gate on the header-declared size after open() and before convert(), so nothing past the cap is decoded. Explicit check rather than a warnings filter — make_thumbnail runs in a worker thread and global warnings state is not thread-safe. Adds tests for the (cap, 2*cap] warn-only window and the at-cap boundary.
- core/thumbnails.py + GET .../attachments/{id}/thumbnail: server-rendered PNG
thumbnails (image downscale; pdf first page via pypdfium2). Extracted a shared
ownership-gated blob resolver used by both get_content and the thumbnail route
- buildAttachmentPreview (composer_attachments.js): image/pdf -> thumbnail,
audio -> <audio> player, text -> lazy snippet; reused by the composer chips and
the sent-message pills (interactive.js). Cookie auth, so direct media src works
- chip kind icons now cover pdf/audio; the upload swap adopts the server's
authoritative kind for styling + icon + preview
- chat.css preview styling; tests for make_thumbnail
Patrick Buckley