Failed to publish message on mqtt broker

Question

I am developing a mobile application that need to implement mqtt. I need to publish the data to the mqtt broker, but it always fail to be published when i try to publish the image data which is the byte array of the image.

It didn't show any error when publish, but it did not published any data on the broker when I try to publish the message. The message can only be published when image data is removed from the payload which is the pichex.

Each data published on the mqtt broker need to be converted into hex ascii code. The byte array of image also need to be converted into hex ascii string code before publish to the broker as it is the requirement of the project.

private void publish(){
    String command = "000000";
    String reserve = "303030303030303030303030303030303030303030303030";
    String tag = "tag";

    name = eTname.getText().toString();
    price = eTprice.getText().toString();
    type = TypeS.getSelectedItem().toString();
    desc = eTdesc.getText().toString();

    userid = MainActivity.getGetuserid();

    String namehex = toHexString(name);
    String pricehex = toHexString(price);
    String typehex = toHexString(type);
    String deschex = toHexString(desc);
    String useridhex = toHexString(userid);

    Bitmap PicBitmap = ((BitmapDrawable)iVpic.getDrawable()).getBitmap();
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    PicBitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
    byte[] picbyte = bos.toByteArray();

    String pichex = bytesToHex(picbyte);

    DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH.mm.ss");
    Date currentTime = Calendar.getInstance().getTime();
    String currentTimeString = df.format(currentTime);

    String payload = "{command:" + command + ", reserve:" + reserve + ", Client ID:" + serverConnectTo + ", Posted name:" + namehex +
            ", Posted Price:" + pricehex + ", Posted Type:" + typehex + ", Posted Description:" + deschex
            + ", Posted Picture:"  + pichex + ", Date Time Posted:"  + currentTimeString +  ", User ID:" + useridhex + "}";

    byte[] encodedPayload = new byte[0];

    try {
        encodedPayload = payload.getBytes();
        MqttMessage message = new MqttMessage(encodedPayload);
        message.setQos(qos);
        mqttClient.publish(topic, message);
    } catch (MqttException e) {
        e.printStackTrace();
    }
}
   public static String toHexString(String input) {
    return String.format("%x", new BigInteger(1, input.getBytes()));
}

public static String bytesToHex(byte[] in) {
    final StringBuilder builder = new StringBuilder();
    for(byte b : in) {
        builder.append(String.format("%02x", b));
    }
    return builder.toString();
}

The hex string value of the picture that need to be published is:

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

This is the image that need to publish

The size of the picture is about 100KB.

The message can be published only when the image data is removed from the payload which is the pichex:

String payload = "{command:" + command + ", reserve:" + reserve + ", Client ID:" + serverConnectTo + ", Posted name:" + namehex + ", Posted Price:" + pricehex + ", Posted Type:" + typehex + ", Posted Description:"  + deschex + ", Date Time Posted:"  + currentTimeString +  ", User ID:" + useridhex + "}";

The message can be received by subscriber if pichex is removed:

{command:000000, reserve:303030303030303030303030303030303030303030303030, Client ID:Server, Posted name:627572676572, Posted Price:392e3939, Posted Type:6e6f6f646c65, Posted Description:616a6468, Date Time Posted:2018-10-14 08.09.29, User ID:696b6f6d61}