AVIF vs WebP: -50% bytes vs +decode cost

AVIF vs WebP: -50% bytes vs +decode cost
Newer format, smaller file. The tradeoff hides in decode time.
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AVIF vs WebP at equal quality: ~30-50% smaller. A 120KB WebP hero -> ~65KB AVIF.
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Decode cost: AVIF decodes ~2-3x slower on low-end CPUs. On a hero LCP image that can add 30-80ms of main-thread work.
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Encode cost: AVIF encoding is ~10-20x slower, painful at build scale.
Serve AVIF via picture with WebP fallback; let weak devices skip the decode tax.
Takeaway: -50KB on the wire, but watch +50ms decode on p75 mobile.