# Reproduce the JPEG tracing tests

Test date: October 15, 2026. The drawings are original CC0 synthetic fixtures. No third-party artwork is copied.

1. Download a .jpg input from this directory and select it in https://filepetal.com/jpg-to-svg/.
2. Convert, inspect the actual SVG preview and download the SVG. Compare dimensions, visible edges and byte count with the saved pair. Compare SHA-256 only within the recorded browser scope; decoders may vary.
3. Open the SVG as XML: count path elements and inspect width, height and viewBox; check whether image or text elements exist. A path count is not a quality score.
4. Independently render the saved SVG at its declared size. Our references use sharp 0.35.4 with librsvg 2.62.91; the *-render.png files are those saved renders. The *-input.png files use sharp's EXIF-aware rotate(). Inspect crops at the same scale.
5. The manifest gives sample positions for row128 fine-line checks and gray-band centers, as well as alpha extrema. These are development measurements, not a visitor pixel-check feature.
6. Regenerate all nine inputs with Python and Pillow 11.3.0: run generate-fixtures.py in an empty working directory. Files are written to generated-jpg-fixtures. JPEG output depends on the Pillow/libjpeg build; compare hashes before claiming exact input reproduction.
7. Error samples: fake.jpg is plain text, truncated.jpg is the first80 bytes of a JPEG, over-side.jpg is4097×1. Each was tested to show an error without a download or preview. Do not interpret this as exhaustive malformed-file testing.

inspect.mjs is the recorded inspection code. It expects the run's .data/jpg-svg-20261015/generated-jpg-fixtures and outputs/{baseline,local}-NAME.svg layout. Run it from the repository root with node and sharp installed. It is an inspection/reproduction helper, not an upload interface.

The existing converter uses a16-slot palette, pathomit4, deterministic sampling and an internal longest edge of1024. This update changes preview and explanations; it does not change the tracing algorithm.