/**
 * Get thumbnail image file name.
 *
 * For an ArcGIS Online Item, the thumbnail property contains values like `thumbnail/thumbnail1681504014799.png`,
 * The string after backslash is the actual file name of the thumbnail image.
 * @param thumbnail
 * @returns file name of the thumbnail image
 *
 * @example
 * ```
 * getThumbnailFileName('thumbnail/thumbnail1681504014799.png');
 * // returns `thumbnail1681504014799.png`
 * ```
 */
export declare const getThumbnailFileName: (thumbnail: string) => string;