Chrome's partial IDCT scaling explains why small JPEGs render differently than in Firefox

Sources: primary, discussion
Summary: Chrome delegates JPEG decoding to Skia and libjpeg-turbo, which decode at the closest eighth-denominator fraction and skip high-frequency coefficients. The author traces small-image rendering differences against Firefox to that partial IDCT path. A correction added on 2026-08-12 attributes part of the difference to the downsampling algorithm rather than the partial IDCT alone.
Why it matters: An icon shipped as a JPEG and rendered at 15px loses its edge softening in one browser and not another.