The XYB color space detail is really interesting — I wasn't aware of how much image-specific engineering went into making AV1 tools work for stills. The libaom 'iq' tuning makes sense in retrospect. So the compression gains in AVIF weren't just inherited from AV1 video work but required significant additional optimization. That makes the JXL comparison more nuanced too — JXL was designed image-first from the start, which might explain why it encodes faster despite similar or better compression ratios.