/**
 * Generates a fake png file for the given file size.
 *
 * @example
 *  // Generates a 2mb file
 * generate('2mb')
 *
 *  // Generates a 300kb file with name avatar.png
 * generate('300kb', 'avatar.png')
 */
export declare function generatePng(fileSize: number | string, fileName?: string): Promise<{
    contents: Buffer;
    size: number;
    name: string;
    mime: string;
}>;