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.
Patrick Buckley