Java Web Socket close (getCloseCode : TOO BIG)

Question

I'm trying to build a chat application with Java server and JS client. It's ok but

when I try to send an image from the client with base64 format, the server closed with the reason TOO BIG.

So how can I increase the transport limit? Or if there's another way to send an image to the server,

please tell me. Thanks. The code below:

The server:

@ServerEndpoint(value = "/chat/{username}", decoders = MessageDecoder.class, encoders = MessageEncoder.class)
public class ChatEndpoint {
    private Session session;
    private static final Set<ChatEndpoint> chatEndpoints = new CopyOnWriteArraySet<>();
    private static HashMap<String, String> users = new HashMap<>();
    static boolean checkAll = true;
    static String userAll;
    @OnOpen
    public void onOpen(Session session, @PathParam("username") String username) throws IOException, EncodeException {
    ...
}
    @OnMessage
    public void onMessage(Session session, Message message) throws IOException, EncodeException, SQLException, ClassNotFoundException {
    broadcast(message); 
}
    ...
    private static void broadcast(Message message) throws IOException, EncodeException {
        chatEndpoints.forEach(endpoint -> {
            synchronized (endpoint) {
                try {
                    endpoint.session.getBasicRemote()
                        .sendObject(message);
                    //System.out.println("end point "+endpoint.session.getUserProperties().get("username"));                    
                } catch (IOException | EncodeException e) {
                    e.printStackTrace();
                }
            }
        });
    }

And the client:

ws = new WebSocket("ws://" + document.location.host + "/Project1.3/chat/" + username);
ws.onMessage = ...
...
function send(to) {
    var content = document.getElementById("message").value;
    $('#message').val('');
    var json = JSON.stringify({
        "from":username,
        "to":to,
        "content":content,
        "type":"text"
    });
    ws.send(json);
}