replace all the images with their HQ version (that is, the one that's been uploaded originally)

twitter_hq_images.js

// ==UserScript==
// @name        Twitter HQ images
// @namespace   https://gist.github.com/RoxasShadow/031eda7f62d09bc8d61d1d5739038329
// @description Replace all the images with their HQ version
// @include     https://twitter.com/*
// @author      Roxas Shadow
// @version     1
// @grant       none
// @run-at      document-idle
// @require     https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js
// @require     https://raw.githubusercontent.com/cowboy/jquery-throttle-debounce/master/jquery.ba-throttle-debounce.min.js
// ==/UserScript==
(function() {
  let hq = function() {
    $('.js-adaptive-photo > img').each(function(i) {
      let $e = $(this);
      let url = $e.attr('src');
      if(!url.endsWith(':orig')) {
        $e.attr('src', url + ':orig');
      }
    });
  };
  
  hq();
  
  $("#timeline").bind("DOMSubtreeModified", $.debounce(500, hq));
})();

/*
  $('#global-actions').append(`
			<li>
        <a role="button" href="#" class="js-tooltip js-dynamic-tooltip" id="hqify" data-placement="bottom" data-original-title="">
          <span class="Icon Icon--search Icon--large"></span>
          <span class="text">HQ</span>
        </a>
      </li>`);
  
  $('#hqify').on('click', (evt) => {
    evt.preventDefault();
    
  	$('img[data-aria-label-part]').each((_, e) => {
    	let src = $(e).attr('src');
    	if(!src.endsWith(':orig')) {
        $(e).attr('src', src + ':orig');
      }
    });
  });
*/