public Mono<Void> deleteImage(String fileId) {
    return Mono.fromRunnable(() -> {
        imageRepository.findById(fileId)
                .map(image -> {
                    Mono<Void> deleteFile = Mono.fromRunnable(() -> {
                        try {
                            Files.deleteIfExists(Paths.get(UPLOAD_ROOT, image.getId() + "-" + image.getName()));
                        } catch (IOException e) {
                            throw new RuntimeException(e);
                        }
                    });
                    Mono<Void> deleteRecord = Mono.fromRunnable(() -> {
                        imageRepository.delete(image);
                    });
                    return Mono.when(deleteFile, deleteRecord).then();
                });
    }).then();
}