01 Formats
AVIF offers maximum compression for modern browsers, WebP is a universal fallback, and JPEG/PNG should be used only where needed. Use picture/source.
02 Sizes
srcset for breakpoints, width/height to prevent CLS, and fetchpriority=high reserved only for the LCP image.
03 Team process
Design exports at 2x, development generates derivatives in CI or on the CDN. Don't ship 4K images to a blog.
