import { IItem, ValidationInfo } from '../../types';
type ThumbnailDimension = {
    width: number;
    height: number;
};
/**
 * Validate an item's thumbnail
 *
 * Living Atlas specific rules:
 * - thumbnail cannot be empty
 * - Must have a custom thumbnail.
 * - The thumbnail must be at least `600 x 400`
 */
export declare const isValidThumbnail: (item: IItem, thumbnailDimension?: ThumbnailDimension) => ValidationInfo;
export {};