export type MediaDerivative = {
    url: string;
    width: number;
    height: number;
    bytes: number;
    sha256: string;
};
export type MediaBuildReport = {
    version: 1;
    images: {
        source: string;
        sha256: string;
        bytes: number;
        variants: MediaDerivative[];
    }[];
    warnings: string[];
};
/** Build-time only: no remote downloads, origin changes, source mutation, or paid image API. */
export declare function responsiveMedia(dist: string, cacheDir: string): Promise<MediaBuildReport>;