How to print an image using a POS Bluetooth printer?

Question

I have an Android POS embedded printer I'm using via Bluetooth.

I'm on .Net Maui 7 application.

I would like to print a bmp image. I'm using the following code :

public async Task PrintImage(string deviceName)
    {
        byte[] imageData;
        string someUrl = "https://...";
        using (var webClient = new WebClient())
        {
            imageData = webClient.DownloadData(someUrl);
        }
    
        byte[] SELECT_BIT_IMAGE_MODE = { 0x1B, 0x2A, 33, (byte)255, 0 };            

        using (BluetoothAdapter bluetoothAdapter = BluetoothAdapter.DefaultAdapter)
        {
            MemoryStream stream = new MemoryStream();
            BluetoothDevice device = (from bd in bluetoothAdapter?.BondedDevices
                                      where bd?.Name == deviceName
                                      select bd).FirstOrDefault();
            try
            {
                using (BluetoothSocket bluetoothSocket = device?.
                    CreateRfcommSocketToServiceRecord(
                    UUID.FromString("00001101-0000-1000-8000-00805f9b34fb")))
                {
                    bluetoothSocket?.Connect();
                    //stream.Write(imageData, 0, imageData.Length);
                    stream.Write(SELECT_BIT_IMAGE_MODE, 0, SELECT_BIT_IMAGE_MODE.Length);
                    stream.Write(imageData, 0, imageData.Length);
                    var bytes = stream.ToArray();
                    bluetoothSocket?.OutputStream.Write(bytes, 0, bytes.Length);
                    bluetoothSocket.Close();
                }
            }
            catch (Exception exp)
            {
                throw exp;
            }
        }
    }

The code runs but the result of the printing contains only some strange characters as in the picture.

Here is the image I want to print. It's Black & White :

And the result :

How can I solve that?