How do I serve WebP with PNG fallback?

Q: How do I serve WebP with PNG fallback?

Use <code>&lt;picture&gt;</code>: <code>&lt;picture&gt;&lt;source type="image/webp" srcset="img.webp"&gt;&lt;img src="img.png" alt="…"&gt;&lt;/picture&gt;</code>. Modern browsers pick WebP; old ones fall back to PNG.

Use <picture>: <picture><source type="image/webp" srcset="img.webp"><img src="img.png" alt="…"></picture>. Modern browsers pick WebP; old ones fall back to PNG.