import { ComparePngOptions } from 'png-visual-compare';
/**
 * Compares a PNG image with an expected PNG image.
 * If the expected image does not exist, it creates it by copying the actual image.
 * @param actualFile - The path or buffer of the actual PNG image.
 * @param expectedFile - The path of the expected PNG image.
 * @param opts - Optional compare options.
 * @returns A promise that resolves to the comparison result.
 */
export declare function comparePNG({ actualFile, expectedFile, createExpectedFileIfMissing, opts, }: {
    actualFile: string | Buffer;
    expectedFile: string;
    createExpectedFileIfMissing: boolean;
    opts?: ComparePngOptions;
}): number;