Fix Humongous Youtube Sidebar -- Feb 2026

resizeYoutubeThumbnails.user.js

// ==UserScript==
// @name         Resize YouTube Thumbnails
// @namespace    http://tampermonkey.net/
// @version      1.2
// @description  Fix humongous youtube sidebar
// @author       Gall
// @match        *://www.youtube.com/*
// @grant        none
// @run-at       document-start
// ==/UserScript==

(function() {
    'use strict';

    var style = document.createElement('style');

    style.innerHTML = `
        /* Force the sidebar to a specific width */
        #secondary {
            max-width: 400px !important;
        }

        #secondary .yt-lockup-view-model__content-image {
            width: 168px !important;
            max-width: 168px !important;
            min-width: 168px !important;
        }

        /* Optional: Hide the skeleton loading shimmer if it ends up being too big */
        #secondary .yt-lockup-view-model__image-container-with-modifiers {
             width: 168px !important;
        }
    `;

    if (document.head) {
        document.head.appendChild(style);
    } else {
        document.documentElement.appendChild(style);
    }

})();