// ==UserScript==
// @name Restore animated thumbnail previews - youtube.com
// @namespace Violentmonkey Scripts seekhare
// @match *://www.youtube.com/*
// @run-at document-start
// @grant GM_addStyle
// @grant GM_xmlhttpRequest
// @version 5.0
// @license MIT
// @author seekhare
// @description To restore animated thumbnail previews. Requires inline video previews to be disabled in your YouTube user settings (Go to https://www.youtube.com/account_playback and set "video previews" to disabled). Not Greasemonkey compatible. v5 Add new method for getting an_webp GIF-style thumbs when not available in YT's new homepage UI or subscription page UI.
// ==/UserScript==
const logHeader = 'UserScript Restore YT Animated Thumbs:';
console.log(logHeader, "enabled.")
Object.defineProperties(Object.prototype,{isPreviewDisabled:{get:function(){return false}, set:function(){}}}); // original method
//2025-07-12 added animatedThumbnailEnabled & inlinePreviewEnabled for new sidebar UI on watch page.
Object.defineProperties(Object.prototype,{animatedThumbnailEnabled:{get:function(){return true}, set:function(){}}});
Object.defineProperties(Object.prototype,{inlinePreviewEnabled:{get:function(){return false}, set:function(){}}});
//2025-07-28 Don't enable the below as seems to break things but I'm leaving here in case of future Youtube change, for reference if needed in future fixes.
//Object.defineProperties(Object.prototype,{isInlinePreviewEnabled:{get:function(){return true}, set:function(){return true}}});
//Object.defineProperties(Object.prototype,{isInlinePreviewDisabled:{get:function(){return true}, set:function(){return true}}});
//Object.defineProperties(Object.prototype,{inlinePreviewIsActive:{get:function(){return false}, set:function(){}}});
//Object.defineProperties(Object.prototype,{inlinePreviewIsEnabled:{get:function(){return false}, set:function(){}}});
fadeInCSS = `img.animatedThumbTarget { animation: fadeIn 0.5s; object-fit: cover;}
@keyframes fadeIn {
0% { opacity: 0; }
100% { opacity: 1; }
}
`;
GM_addStyle(fadeInCSS);
const homeUrl = 'https://www.youtube.com/';
const searchUrl = 'https://www.youtube.com/results?search_query='; // use like "https://www.youtube.com/results?search_query=IDabc123", for anonymous requests is rate limited
const ytImageRootUrl = 'https://i.ytimg.com/';
const ytImageNames = ['hq1.jpg', 'hq2.jpg', 'hq3.jpg']; // e.g. https://i.ytimg.com/vi/UujGYE5mOnI/hq1.jpg
const carouselDelay = 500; //milliseconds, how long to display each image.
var an_webpUrlDictionary = {}; //store prefetched an_webp urls for videoIDs in homepage/subscription page of new YT lockup style UI.
var an_webpUrlDictionaryFailedCount = {}; //store failed fetch attempt count to give up after certain number.
const updateDictionaryBatchSize = 10;
const updateDictionaryFailedCountLimit = 5;
const an_webpDictionaryWorkerInterval = 3500; //milliseconds
async function animatedThumbsEventEnter(event) {
//console.debug(logHeader, 'enter', event);
var target = event.target;
//console.debug(logHeader, 'target', target);
//Below are some exceptions where we don't want to apply the carousel fallback and can't except these in the mutation observer as child elements are not present then.
if (target.querySelector('ytd-rich-grid-media') != null) { // don't apply to old media grid tiles for users with homepage or subscription page still on old version, as these have an_webp available.
target.removeEventListener('mouseenter', animatedThumbsEventEnter);
target.removeEventListener('mouseleave', animatedThumbsEventLeave);
return false
} else if (target.querySelector('badge-shape.badge-shape-wiz--thumbnail-live') != null) { // don't apply to video tiles that are live.
target.removeEventListener('mouseenter', animatedThumbsEventEnter);
target.removeEventListener('mouseleave', animatedThumbsEventLeave);
return false
} else if (target.querySelector('ytm-shorts-lockup-view-model') != null) { // don't apply to shorts tiles.
target.removeEventListener('mouseenter', animatedThumbsEventEnter);
target.removeEventListener('mouseleave', animatedThumbsEventLeave);
return false
} else if (target.querySelector('path[d="M2.81,2.81L1.39,4.22L8,10.83V19l4.99-3.18l6.78,6.78l1.41-1.41L2.81,2.81z M10,15.36v-2.53l1.55,1.55L10,15.36z"]') != null) { // don't apply to video tiles that have inline videos disabled by YT as these have the an_webp thumbs available, these videos have a crossed out play icon SVG but otherwise no other identifier hence the strange selector.
target.removeEventListener('mouseenter', animatedThumbsEventEnter);
target.removeEventListener('mouseleave', animatedThumbsEventLeave);
return false
}
//Overlay target to attach created image node should be present
var overlaytag = target.querySelector('div.yt-thumbnail-view-model__image');
if (overlaytag == null) {
target.removeEventListener('mouseenter', animatedThumbsEventEnter);
target.removeEventListener('mouseleave', animatedThumbsEventLeave);
return false
}
var atag = target.querySelector('a');
//console.debug(logHeader, 'atag', atag);
if (atag.videoId === undefined) {
//extract videoId from href and store on an attribute
var videoId = atag.getAttribute('href').match(/watch\?v=([^&]*)/)[1]; //the href is like "/watch?v=IDabc123&t=123" so regex.
//console.debug(logHeader, 'videoId', videoId);
atag.videoId = videoId;
}
if (atag.animatedThumbType === undefined || atag.animatedThumbType == 'carousel') {
//do search url request to get animated thumb URL and store on attribute "srcAnimated"
var thumbUrl = getAnimatedThumbURLDictionary(atag.videoId);
if (thumbUrl != null) {
atag.animatedThumbType = 'an_webp';
atag.srcAnimated = thumbUrl;
} else {
//if no animated thumb available use carousel fallback.
atag.animatedThumbType = 'carousel';
}
}
var animatedImgNode = document.createElement("img");
animatedImgNode.videoId = atag.videoId;
animatedImgNode.setAttribute("id", "thumbnail");
animatedImgNode.setAttribute("class", "style-scope ytd-moving-thumbnail-renderer fade-in animatedThumbTarget"); //animatedThumbTarget is custom class, others are Youtube
if (atag.animatedThumbType == 'an_webp') {
animatedImgNode.setAttribute("src", atag.srcAnimated);
} else if (atag.animatedThumbType == 'carousel') {
animatedImgNode.carouselIndex = 0;
updateCarousel(animatedImgNode);
animatedImgNode.timer = setInterval(updateCarousel, carouselDelay, animatedImgNode);
}
overlaytag.appendChild(animatedImgNode);
return true
}
async function animatedThumbsEventLeave(event) {
//console.debug(logHeader, 'leave', event);
try {
var animatedImgNodeList = event.target.querySelectorAll('img.animatedThumbTarget');
for (var animatedImgNode of animatedImgNodeList) {
clearTimeout(animatedImgNode.timer);
animatedImgNode.remove();
}
} catch {
return false
}
return true
}
function updateCarousel(carouselImgNode) {
var index = carouselImgNode.carouselIndex;
//console.debug(logHeader, 'index', index);
var imgURL = ytImageRootUrl + 'vi/' + carouselImgNode.videoId + '/' + ytImageNames[index];
carouselImgNode.setAttribute("src", imgURL);
var nextIndex = (index+1) % ytImageNames.length;
carouselImgNode.carouselIndex = nextIndex;
}
function makeGetRequest(url) {
return new Promise((resolve, reject) => {
GM_xmlhttpRequest({
method: "GET",
url: url,
anonymous: true, // make request anonymous, without cookies so doesn't affect user's search history.
onload: response => resolve(response),
onerror: error => reject(error)
});
});
}
function getAnimatedThumbURLDictionary(videoId) {
return an_webpUrlDictionary[videoId]
}
function runPageCheckForExistingElements() {
//Can run this just incase some elements were already created before observer set up.
var list = document.getElementsByTagName("ytd-rich-item-renderer");
for (var element of list) {
//console.debug(logHeader, element);
element.addEventListener('mouseenter', animatedThumbsEventEnter);
element.addEventListener('mouseleave', animatedThumbsEventLeave);
}
}
function setupMutationObserver() {
console.log(logHeader, "Enabling carousel fallback where an_webp not available.")
const targetNode = document;
//console.debug('targetNodeInit',targetNode);
const config = {attributes: false, childList: true, subtree: true};
const callback = (mutationList, observer) => {
for (const mutation of mutationList) {
//console.debug(logHeader, "Mutation", mutation);
for (const element of mutation.addedNodes) {
if (element.nodeName === 'YTD-RICH-ITEM-RENDERER') {
//console.debug(logHeader, "Adding event listeners to element", element);
element.addEventListener('mouseenter', animatedThumbsEventEnter);
element.addEventListener('mouseleave', animatedThumbsEventLeave);
}
}
}
}
const observer = new MutationObserver(callback);
observer.observe(targetNode, config);
runPageCheckForExistingElements();
}
document.addEventListener("DOMContentLoaded", function(){
setupMutationObserver()
const an_webpDictionaryWorker = setInterval(updateDictionary, an_webpDictionaryWorkerInterval);
});
async function updateDictionary() {
if (window.location.pathname === '/' || window.location.pathname === '/feed/subscriptions' ) {
var list = document.getElementsByTagName("ytd-rich-item-renderer");
var listToProcess = []; //Process upto 10 videoIds at once
for (var target of list) {
var atag = target.querySelector('a');
//console.debug(logHeader, 'atag', atag);
if (atag.videoId != undefined && (an_webpUrlDictionary[atag.videoId] != undefined || an_webpUrlDictionaryFailedCount[atag.videoId] > updateDictionaryFailedCountLimit)) {//if already processed then skip
continue
} else if (target.querySelector('ytd-rich-grid-media') != null) { // don't apply to old media grid tiles for users with homepage or subscription page still on old version, as these have an_webp available.
continue
} else if (target.querySelector('badge-shape.badge-shape-wiz--thumbnail-live') != null) { // don't apply to video tiles that are live.
continue
} else if (target.querySelector('ytm-shorts-lockup-view-model') != null) { // don't apply to shorts tiles.
continue
} else if (target.querySelector('path[d="M2.81,2.81L1.39,4.22L8,10.83V19l4.99-3.18l6.78,6.78l1.41-1.41L2.81,2.81z M10,15.36v-2.53l1.55,1.55L10,15.36z"]') != null) { // don't apply to video tiles that have inline videos disabled by YT as these have the an_webp thumbs available, these videos have a crossed out play icon SVG but otherwise no other identifier hence the strange selector.
continue
}
var videoId = atag.getAttribute('href').match(/watch\?v=([^&]*)/)[1]; //the href is like "/watch?v=IDabc123&t=123" so regex.
//console.debug(logHeader, 'videoId', videoId);
atag.videoId = videoId;
listToProcess.push(videoId);
if (listToProcess.length == updateDictionaryBatchSize) {
break
}
}
//console.debug(logHeader, 'listToProcess', listToProcess);
if (listToProcess.length == 0) {
return
}
var searchQueryString = '%22' + listToProcess.join('%22%7C%22') +'%22'; // %7C = | pipe char, %22 = quote "
var response = await makeGetRequest(searchUrl+searchQueryString);
//console.debug('response', response);
if (response.status == 200) {
for (videoId of listToProcess) {
var trimmedResponseIndex = response.responseText.indexOf('an_webp/'+videoId);
if (trimmedResponseIndex == -1) {
console.log(logHeader, 'No an_webp url in response for '+videoId);
incrementFailedCount(videoId);
continue
}
var trimmedResponse = response.responseText.substring(trimmedResponseIndex, trimmedResponseIndex+106) //106 char is length of an_webp URL path always.
//console.debug(logHeader, 'trimmedResponseIndex',trimmedResponseIndex);
//console.debug(logHeader, 'trimmedResponse',trimmedResponse);
try {
var url = ytImageRootUrl+trimmedResponse.replaceAll('\\u0026', '&');
an_webpUrlDictionary[videoId] = url;
continue
} catch {
incrementFailedCount(videoId);
continue
}
}
}
}
//console.debug(logHeader, 'an_webpUrlDictionary', an_webpUrlDictionary);
//console.debug(logHeader, 'an_webpUrlDictionaryFailedCount', an_webpUrlDictionaryFailedCount);
}
function incrementFailedCount(videoId) {
if (an_webpUrlDictionaryFailedCount[videoId] === undefined) {
an_webpUrlDictionaryFailedCount[videoId] = 1;
} else {
an_webpUrlDictionaryFailedCount[videoId] += 1;
}
}
