Original PickImageColors source-file lab, 2026-10-25.
Does PNG compression change a picked color?
Run: python reproduce.py --case png-compression-color-values --out rerun
Dependency: Pillow. Recorded runtime: Python 3.12.14, Pillow 12.3.0, libwebp 1.6.0.
Measurements are local source-file computations, not browser observations. Library-dependent compression sizes and quantizer choices may change with runtime.
We tested Pillow’s PNG compression setting on an opaque, unprofiled RGB fixture. We did not test a third-party optimizer, a managed display or every PNG export preset. The measured byte counts describe these files only.
