import { ApiPropertyOptions } from '@nestjs/swagger';
/**
 * Decorator for the 'background' property of a thumbnail.
 * Allows specifying one or more HEX color codes (solid or gradient).
 * Supports dynamic validation of array length through options.
 *
 * @param {ApiPropertyOptions} options - Swagger and validation options.
 * @returns {PropertyDecorator} Combined decorators for transformation, validation, and API documentation.
 */
export declare function ThumbnailBackground(options?: ApiPropertyOptions): PropertyDecorator;