/** Pure helpers for the worker photo methods (no I/O). */
export interface MultipartPart {
    name: string;
    value: string | Uint8Array;
    filename?: string;
    contentType?: string;
}
/**
 * Zero-dep multipart/form-data assembly. Part names/headers mirror the
 * recorded production upload: a "json" part (no filename) and a "datafile"
 * part with filename + Content-Type.
 */
export declare function buildMultipart(parts: MultipartPart[]): {
    contentType: string;
    body: Uint8Array;
};
/** Magic-byte detection; explicit contentType params always override this. */
export declare function sniffImageContentType(bytes: Uint8Array): string;
/** Accepts raw bytes or a base64 string (the flow-step convention). */
export declare function imageToBytes(image: Uint8Array | string): Uint8Array;