display.html

        <script src="underscore-min.js"></script>
        <script src="jquery-1.11.0.min.js"></script>
        <script type="text/javascript">
                ws = new WebSocket("ws://puku.local:8001");
                ws.onmessage = function(evt) {
                    console.log('hi')
                   $('#display').html('<img src="'+ evt.data +'"/>')
                };
        </script>

index.html

ws = new WebSocket("ws://puku.local:8001");

                input = document.querySelector('input')
                input.style.display = 'block'
                $(input).on('change', function(evt) {
                    var file = input.files[0]
                    var fr = new FileReader();
                    fr.onload = function() {
                        ws.send(fr.result)
                    };
                    fr.readAsDataURL(file)
                })

                ws.onmessage = function(evt) {
                    var $success = $('<div>').css({
                        width: '100%',
                        height: '100%',
                        backgroundColor: 'green',
                        position: 'absolute',
                        top: 0,
                        left: 0,
                    })
                    $('body').append($success)
                    setTimeout(function() {
                        $success.fadeOut(function() { $success.remove() })
                    }, 500)
                }

server.js

fs = require('fs')
var ws = require("nodejs-websocket")
images = []
var server = ws.createServer(function (conn) {

    console.log("New connection")
    conn.sendText(images[images.length-1] || '')

    conn.on("text", function (str) {
        images.push(str)
        console.log('sending new image...')
        conn.sendText(str)
        fs.writeFile('images.json', JSON.stringify(images))
    })

    conn.on("close", function (code, reason) {
        console.log("Connection closed")
    })
}).listen(8001)