Lazyload with browser snapping + nicescroll

HTML

<div class="container">
  
  <div class="box">
        <img src="http://www.appelsiini.net/projects/lazyload/img/grey.gif" data-original="http://www.appelsiini.net/projects/lazyload/img/bmw_m1_hood.jpg" width="500" height="500" alt="BMW M1 Hood">
    </div>
  

</div>

CSS

.container {height: auto; overflow: hidden; width: 500px;}
.box {width: 500px; height: 700px; display: block;}

JavaScript

/* jquery.nicescroll
-- version 2.9.6
-- copyright 2011-12 InuYaksa*2012
-- licensed under the MIT
--
-- http://areaaperta.com/nicescroll
-- https://github.com/inuyaksa/jquery.nicescroll
--
*/

(function(jQuery){

  // globals
  var domfocus = false;
  var mousefocus = false;
  var zoomactive = false;
  var tabindexcounter = 5000;
  var ascrailcounter = 2000;
  
  var $ = jQuery;  // sandbox
 
  // http://stackoverflow.com/questions/2161159/get-script-path
  function getScriptPath() {
    var scripts=document.getElementsByTagName('script');
    var path=scripts[scripts.length-1].src.split('?')[0];
    return (path.split('/').length>0) ? path.split('/').slice(0,-1).join('/')+'/' : '';
  }
  var scriptpath = getScriptPath();

  // derived by http://blog.joelambert.co.uk/2011/06/01/a-better-settimeoutsetinterval/
  var setAnimationFrame = (function(){
    return  window.requestAnimationFrame       || 
            window.webkitRequestAnimationFrame || 
            window.mozRequestAnimationFrame    || 
            window.oRequestAnimationFrame      || 
            window.msRequestAnimationFrame     || 
            false;
  })();
  var clearAnimationFrame = (function(){
    return  window.cancelRequestAnimationFrame       || 
            window.webkitCancelRequestAnimationFrame || 
            window.mozCancelRequestAnimationFrame    || 
            window.oCancelRequestAnimationFrame      || 
            window.msCancelRequestAnimationFrame     || 
            false;
  })();  
  
  var NiceScrollClass = function(myopt,me) {

    var self = this;

    this.version = '2.9.6';
    this.name = 'nicescroll';
    
    this.me = me;
    
    this.opt = {
      doc:$("body"),
      win:false,
      zindex:9000,
      cursoropacitymin:0,
      cursoropacitymax:1,
      cursorcolor:"#424242",
      cursorwidth:"5px",
      cursorborder:"1px solid #fff",
      cursorborderradius:"5px",
      scrollspeed:10,
      mousescrollstep:10,
      touchbehavior:false,
     ...