instaload.user.js

// ==UserScript==

// @name          Instaload

// @namespace     https://fysac.me

// @description   Autoloads the next page of photos on Instagram as you scroll down.

// @include       http://instagram.com/*

// ==/UserScript==

$(window).scroll(function() {
   if ($(window).scrollTop() + $(window).height() > $(document).height() - 100){
       document.getElementsByClassName('more-photos-enabled')[0].click();
   }
});