isGenAI controlled image-density examples — 2026-09-27

These three PNG files contain the same 1200 x 900 software-drawn RGB grid.
They contain no person, camera scene or detection benchmark.

controlled-300ppi.png: pHYs 11811 x 11811 pixels/metre, unit 1.
Multiplying by 0.0254 gives 299.9994 pixels/inch, commonly rounded to 300.
controlled-unitless.png: pHYs 1 x 1 with unit 0, an aspect ratio only.
controlled-no-density.png: no pHYs density record.

The manifest includes file hashes, decoded-pixel hashes and an independent
Sharp header read. Sharp reports interpreted density; in this version, a file without pHYs
returns a default 72 even though no physical-density record exists. That value
is not stored in the fixture. Inspect raw pHYs values for exact conversion. Equal pixels can carry different print-density records.

Generate from repository root with:
node scripts/generate-image-density-examples.mjs
Encoding-library versions can affect compressed bytes. Compare decoded hashes
and raw density values when reproducing with a different encoder version.

These original generated fixtures and pixel pattern are dedicated under CC0 1.0:
https://creativecommons.org/publicdomain/zero/1.0/
This dedication does not cover the software dependencies or linked standards.