export declare const USER_AVATAR_MAX_BYTES: number;
type UserAvatarMime = 'image/png' | 'image/jpeg' | 'image/webp';
export type UserAvatarResult<T> = {
    ok: true;
    data: T;
} | {
    ok: false;
    error: string;
    status: 400 | 404;
};
export declare function readUserAvatar(): Promise<UserAvatarResult<{
    buffer: Buffer;
    contentType: UserAvatarMime;
}>>;
export declare function writeUserAvatar(base64: string, mimeType: string): Promise<UserAvatarResult<{}>>;
export declare function deleteUserAvatar(): Promise<UserAvatarResult<{}>>;
export {};