Execute javascript (PhantomJS) after load full webpage

Question

I am trying to get screenshot of some webpages using PhantomJS 2.0. However, I need the script runs just after the webpage is loaded completely.

Ex.: In this wepage http://esed.nl/druk-en-printwerk/esed-druk-en-printwerk/verpakkingsdrukwerk every time I get the screen the result it's just a blank image with a loading red gif. Like it

This is my code.

#!/usr/bin/env phantomjs 
function waitFor(testFx, onReady, timeOutMillis) {
var maxtimeOutMillis = timeOutMillis ? timeOutMillis : 5000, //< Default Max Timout is 5s
    start = new Date().getTime(),
    condition = (typeof(testFx) === "string" ? eval(testFx) : testFx()), //< defensive code
    interval = setInterval(function() {
        if ( (new Date().getTime() - start < maxtimeOutMillis) && !condition ) {
            // If not time-out yet and condition not yet fulfilled
            condition = (typeof(testFx) === "string" ? eval(testFx) : testFx()); //< defensive code
        } else {
            if(!condition) {
                // If condition still not fulfilled (timeout but condition is 'false')
                console.log("'waitFor()' timeout");
                phantom.exit(1);
            } else {
                // Condition fulfilled (timeout and/or condition is 'true')
                console.log("'waitFor()' finished in " + (new Date().getTime() - start) + "ms.");
                typeof(onReady) === "string" ? eval(onReady) : onReady(); //< Do what it's supposed to do once the condition is fulfilled
                clearInterval(interval); //< Stop this interval
            }
        }
    }, 500); //repeat check every 500ms
};

var system = require('system')
var width = window.parseInt(system.args[1])
var height = window.parseInt(system.args[2])
var url = system.args[3]
var relative_path = system.args[4]

var page = require('webpage').create();
var resources = [];

page.onResourceRequested = function(request) {
  resources[request.id] = request.stage;
};

page.onResourceReceived = function(response) {
  resources[response.id] = response.stage;
};

page.onResourceError = function(resourceError) {
    page.reason = resourceError.errorString;
    page.reason_url = resourceError.url;
};

//Loading whole webpage
page.viewportSize = {
  width: 2000,
  height: 10000
};

page.open(url, function(status) {
  if (status !== 'success') {
    console.log("Error opening url \"" + page.reason_url + "\": " +                  page.reason );
  } else {
    waitFor(function() {
      page.viewportSize = { width: width, height: height };
      page.render(relative_path);
    }, 10000);
  }
  phantom.exit();
});

So, I need the screen when the page is completely loaded. Someone has any idea how could I do it?