I spent last month migrating 23 client sites from JPEG/PNG to WebP and AVIF. Here's what I wish someone told me before I started. AVIF vs WebP: the real numbers AVIF is about 30% smaller than WebP at the same quality level. But Safari support is still patchy — if your traffic is 40%+ iOS, you need <picture> tags with WebP fallback. No way around it. The biggest win wasn't the format The single biggest reduction came from capping max image width at 12...