/**
 * Scan `html` for plain `<img>` tags whose src resolves to a real file
 * inside `publicDir`, probe for sibling-format files (e.g. `hero.webp`
 * next to `hero.jpg`), and wrap matches in `<picture>` with `<source>`
 * entries for each sibling that actually exists on disk.
 *
 * Returns the rewritten HTML. If no `<img>` matches or no siblings are
 * found, returns the input unchanged (no allocations beyond the scan).
 */
export declare function rewriteImagesWithSiblings(html: string, options: AutoSiblingOptions): Promise<string>;
export declare interface AutoSiblingOptions {
  publicDir: string
  formats?: Array<{ ext: string, mime: string }>
}
