import type { RequestHandler } from 'express';
import type { FieldNameSet } from '../types/field';
import type { ValidationOptions } from '../types/options';
type IsImageOptions = Partial<Pick<ValidationOptions, 'limit' | 'required' | 'allowedMimeTypes'>>;
/**
 * Express middleware to check if uploaded files are images.
 *
 * Supports optional `required` and `limit` settings.
 * @param { FieldNameSet } field Field name or array of field names to validate.
 * @param { IsImageOptions } [options] Validation options.
 * @returns { RequestHandler } Express middleware function.
 */
export declare function isImage(field: FieldNameSet, options?: IsImageOptions): RequestHandler;
export {};