/**
 * Image asset helpers — base64 / data-url decode + MIME sniffing + extension
 * mapping. Pure functions reused across vendor providers.
 */
export interface SniffedImage {
    mimeType: string;
    fileExtension: string;
}
/** Detect a common image format from its leading bytes. Defaults to PNG. */
export declare function sniffImageMimeType(buffer: Buffer | Uint8Array): SniffedImage;
/** Map a MIME type to a canonical file extension (no dot). */
export declare function imageFileExtensionForMimeType(mimeType: string | undefined): string;
export interface ParsedImageDataUrl {
    mimeType: string;
    base64: string;
}
/**
 * Parse a `data:image/<format>;base64,<payload>` URL.
 * Returns null on malformed input or non-image data URLs.
 */
export declare function parseImageDataUrl(input: string): ParsedImageDataUrl | null;
/** Convert a base64 string into a sniffed asset descriptor. */
export declare function imageAssetFromBase64(params: {
    base64: string;
    mimeType?: string;
    fileName?: string;
}): {
    buffer: Buffer;
    mimeType: string;
    fileName?: string;
};
/** Convert a data URL into a sniffed asset descriptor. */
export declare function imageAssetFromDataUrl(input: string, fileName?: string): {
    buffer: Buffer;
    mimeType: string;
    fileName?: string;
} | null;
/** Best-effort MIME type from a file name (suffix only). */
export declare function mimeTypeFromFileName(fileName: string | undefined): string | undefined;