// ==UserScript==
// @name         Twitter Image :orig Promoter
// @version      0.1
// @description  Automatically promotes twitter image links to :orig, such as from :large.
// @author       Cro
// @match        https://pbs.twimg.com/media/*
// @grant        none
// @namespace https://greasyfork.org/users/10865
// @downloadURL none
// ==/UserScript==

// Check if this page contains a single image whose source is also the location.
var image = document.getElementsByTagName('img')[0];
var loc = location.toString();

if (image && image.getAttribute('src') == loc)
{
    // Remove any modifier and append :orig.
    if (!loc.match(/:orig$/))
    {
        if (loc.indexOf(':') != loc.lastIndexOf(':'))
        {
            loc = loc.substr(0, loc.lastIndexOf(':'));
        }

        window.location = loc + ':orig';
    }
}