getstream_chat_service5.dart

  @override
  Future<void> sendPhotoAsMessageToTheSelectedUser({
    required String channelId,
    required int sizeOfTheTakenPhoto,
    required String pathOfTheTakenPhoto,
  }) async {
    final randomMessageId = const Uuid().v1();

    final signedInUserOption = await _firebaseAuth.getSignedInUser();
    final signedInUser = signedInUserOption.fold(
      () => throw Exception("Not authanticated"),
      (user) => user,
    );
    final user = User(id: signedInUser.id);

    streamChatClient
        .sendImage(
      AttachmentFile(
        size: sizeOfTheTakenPhoto,
        path: pathOfTheTakenPhoto,
      ),
      channelId,
      "messaging",
    )
        .then((response) {
      // Successful upload, you can now attach this image
      // to an message that you then send to a channel
      final imageUrl = response.file;
      final image = Attachment(
        type: 'image',
        imageUrl: imageUrl,
      );

      final message = Message(
        user: user,
        id: randomMessageId,
        createdAt: DateTime.now(),
        attachments: [image],
      );

      streamChatClient.sendMessage(message, channelId, "messaging");
    });
  }