SurveyNotesXL.js

// ==UserScript==
// @name         Survey Notes XL
// @namespace    http://elza.me
// @version      0.1
// @description  Default to XL images. Go big or go home!
// @author       Hayden Elza
// @match        http://digicoll.library.wisc.edu/cgi-bin/SurveyNotes/*
// @require      https://code.jquery.com/jquery-latest.js
// ==/UserScript==

(function() {
    'use strict';

    $('a[href*="/cgi-bin/SurveyNotes/SurveyNotes-idx?"]').each(function() {
        $(this).attr("href", $(this).attr("href") + '&isize=XL');
    });

    $(document).keydown(function(e) {
        // Left
        if(e.which == 37) {
            $('.navtable tr:has(.navlink):contains("Page")').each(function() {
                window.location.href = $(this).find(":nth-child(2) a").attr("href");
            });
        // Right
        } else if(e.which == 39) {
            $('.navtable tr:has(.navlink):contains("Page")').each(function() {
                window.location.href = $(this).find(":nth-child(4) a").attr("href");
            });
        }
    });
})();