diff --git a/README.md b/README.md
index 2db54ee..af72182 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ To use it, copy the [`./src/player.html`](src/player.html) file into a folder th
 * Custom video playback controls (fullscreen, play, pause, mute, etc, volume, playback rate)
 * Picture-in-picture support
 * Progress bar with timestamp preview thumbnail on hover
-* Video thumbnail generation, with concurrency configuration (default 1)*
+* Video thumbnails: [using prerendered thumbnail files](#thumbnails), or rendered on-the-fly in-browser
 * Animated thumbnails**
 * Thumbnail caching using `localStorage`, check cache size, clear cache
 * Select your own custom theme color
@@ -34,19 +34,37 @@ To use it, copy the [`./src/player.html`](src/player.html) file into a folder th
 
 \** Animated thumbnails can consume a lot of data. The experience may degrade on slower network connections
 
-## Supported Browsers
+<a name="thumbnails"></a>
+## Pre-rendered server-side thumbnails
+
+`player.html` can use server-side thumbnails for any video that has one available. It will fall back to generating thumbnails in the browser otherwise. The server-side thumbnail files must follow the common filename convention of using the video file name, with the extension replaced with an image extension, in the same folder as the video. Note: The image files must be shown by your web server's directory browsing (may require mime-type adjustments on some servers) feature to show up in `player.html`.
+
+### Naming example:
+
+* Video filename: `myVideo.mp4`
+* Matching thumbnail filename: `myVideo.jpg` 
+
+### How to pre-render thumbnails
+
+The easiest way to create thumbnails from video files is on the command-line with [`ffmpeg`](https://ffmpeg.org/). The following command will create a JPEG thumbnail (`myVideo.jpg`) from the video frame 5 seconds into `myVideo.mp4`: `ffmpeg -i myVideo.mp4 -ss 00:00:05.000 -vframes 1 myVideo.jpg`. Loop over folders of video files using your preferred shell (bash, cmd, powershell, etc) to process many videos.
+
+### Supported thumbnail image formats/extensions
+* GIF
+* JPEG
+* JPG
+* PNG
+* WEBP
+
+## Supported browsers
 
 The latest version of these browsers is supported:
 
 * Edge (Chromium)
-* Edge (Xbox EdgeHTML)†
 * Firefox
 * Safari (Mac, iPadOS, iOS)
 * Chrome
 
-† Deprecated: EdgeHTML is only supported on Xbox as it has been replaced on Windows 10.
-
-## Supported Web Servers
+## Supported web servers
 
 The latest version of these web servers (others may work as well):
 
@@ -63,4 +81,4 @@ The latest version of these web servers (others may work as well):
 
 * [MIT](./LICENSE)
 
-&copy; 2021 Paul Ellis
+&copy; 2022 Paul Ellis
diff --git a/src/player.html b/src/player.html
index 8daa8bb..2a62127 100644
--- a/src/player.html
+++ b/src/player.html
@@ -4,7 +4,7 @@
   <title>player.html</title>
   <meta charset='utf-8'>
   <meta name='description' content='Drop player.html in a folder of videos and play them on the web' />
-  <meta name='version' content='2.2.6'>
+  <meta name='version' content='2.2.7'>
   <meta name='Copyright' content='©2021 Paul Ellis'>
   <meta name='license' content='https://opensource.org/licenses/MIT'>
   <meta name='apple-mobile-web-app-status-bar-style' content='black'>
@@ -2036,11 +2036,11 @@
   
   <!-- folder.api -->
   <script defer>
-    // folder.api (https://github.com/pseudosavant/folder.api): v1.0.2
-    (function folderApiIIFE(global) {
-      'use strict';
+    // folder.api: version 1.0.3
+  (function folderApiIIFE(global) {
+    'use strict';
 
-      function urlType(url) {
+      const urlType = (url) => {
         if (isHiddenFileOrFolder(url)) {
           return 'hidden';
         } else if (isFolder(url)) {
@@ -2052,7 +2052,7 @@
         }
       }
 
-      function isFile(url) {
+      const isFile = (url) => {
         const parsed = new URL(url);
         const finalPosition = parsed.pathname.lastIndexOf('/') + 1;
         const finalPart = parsed.pathname.substring(finalPosition);
@@ -2063,31 +2063,31 @@
       const hasPeriod = (s) => s.indexOf('.') >= 0;
       const isFolder = (url) => !isFile(url);
 
-      function isHiddenFileOrFolder(url) {
+      const isHiddenFileOrFolder = (url) => {
         const reHidden = /\/\..+$/i;
         return url.toString().match(reHidden);
       }
 
-      function parentFolder(url) {
+      const parentFolder = (url) => {
         // Only add the first slash if the URL doesn't have it at the end
         const append = (url.endsWith('/') ? '../' : '/../');
         const parentUrl = new URL(url + append).toString();
         return parentUrl;
       }
 
-      function urlToFoldername(url) {
+      const urlToFoldername = (url) => {
         var pieces = url.split('/');
         return pieces[pieces.length - 2]; // Return piece before final `/`
       }
 
-      function urlToFilename(url) {
+      const urlToFilename = (url) => {
         const re = /\/([^/]+)$/;
         const parts = re.exec(url);
         return (parts && parts.length > 1 ? parts[1] : url);
       }
 
       // Parses each node's metadata by running a function on each entry
-      async function linkToMetadata(node, server) {
+      const linkToMetadata = async (node, server) => {
         return (
           typeof servers[server] === 'function' ?
             servers[server](node) :
@@ -2095,7 +2095,7 @@
         );
       }
 
-      async function getHeaderData(url) {
+      const getHeaderData = async (url) => {
         if (!url) return {};
 
         try {
@@ -2108,7 +2108,7 @@
         }
       }
 
-      async function getServer(url) {
+      const getServer = async (url) => {
         const headers = await getHeaderData(url);
 
         if (isNginx(headers)) {
@@ -2154,11 +2154,11 @@
             const dateResults = dateRe.exec(dateNode.textContent);
 
             if (dateResults) {
-              const y = toInteger(dateResults[1]) || undefined;
-              const m = toInteger(dateResults[2]) || undefined;
-              const d = toInteger(dateResults[3]) || undefined;
-              const hours = toInteger(dateResults[4]) || undefined;
-              const mins = toInteger(dateResults[5]) || undefined;
+              const d =     (toInteger(dateResults[1]) >= 0 ? toInteger(dateResults[1]) : undefined);
+              const m =     (isString(dateResults[2])       ? dateResults[2] : undefined);
+              const y =     (toInteger(dateResults[3]) >= 0 ? toInteger(dateResults[3]) : undefined);
+              const hours = (toInteger(dateResults[4]) >= 0 ? toInteger(dateResults[4]) : undefined);
+              const mins =  (toInteger(dateResults[5]) >= 0 ? toInteger(dateResults[5]) : undefined);
               metadata.date = new Date(`${m}-${d}, ${y} ${hours}:${mins}:00`);
             }
           }
@@ -2196,14 +2196,14 @@
           const results = re.exec(text);
 
           if (!results) return metadata;
-          const d = toInteger(results[1]) || undefined;
-          const m = results[2] || undefined;
-          const y = toInteger(results[3]) || undefined;
-          const hours = toInteger(results[4]) || undefined;
-          const mins = toInteger(results[5]) || undefined;
+          const d =     (toInteger(results[1]) >= 0 ? toInteger(results[1]) : undefined);
+          const m =     (isString(results[2])       ? results[2] : undefined);
+          const y =     (toInteger(results[3]) >= 0 ? toInteger(results[3]) : undefined);
+          const hours = (toInteger(results[4]) >= 0 ? toInteger(results[4]) : undefined);
+          const mins =  (toInteger(results[5]) >= 0 ? toInteger(results[5]) : undefined);
           metadata.date = new Date(`${m}-${d}, ${y} ${hours}:${mins}:00`);
 
-          metadata.size = toInteger(results[6]) || undefined;
+          metadata.size = (isNumber(toInteger(results[6])) ? toInteger(results[6]) : undefined);
 
           return metadata;
         },
@@ -2218,14 +2218,14 @@
           const results = re.exec(text);
           if (!results) return metadata;
 
-          const m = toInteger(results[1]) || undefined;
-          const d = toInteger(results[2]) || undefined;
-          const y = toInteger(results[3]) || undefined;
-          const hours = toInteger(results[4]) || undefined;
-          const mins = toInteger(results[5]);
+          const d =     (toInteger(results[1]) >= 0 ? toInteger(results[1]) : undefined);
+          const m =     (isString(results[2])       ? results[2] : undefined);
+          const y =     (toInteger(results[3]) >= 0 ? toInteger(results[3]) : undefined);
+          const hours = (toInteger(results[4]) >= 0 ? toInteger(results[4]) : undefined);
+          const mins =  (toInteger(results[5]) >= 0 ? toInteger(results[5]) : undefined);
           metadata.date = new Date(`${m}-${d}, ${y} ${hours}:${mins}:00`);
 
-          metadata.size = toInteger(results[7]) || undefined;
+          metadata.size = (isNumber(toInteger(results[7])) ? toInteger(results[7]) : undefined);
 
           return metadata;
         },
@@ -2265,20 +2265,20 @@
           const results = re.exec(text);
 
           if (!results) return metadata;
-          const d = toInteger(results[1]) || undefined;
-          const m = results[2] || undefined;
-          const y = toInteger(results[3]) || undefined;
-          const hours = toInteger(results[4]) || undefined;
-          const mins = toInteger(results[5]) || undefined;
+          const d =     (toInteger(results[1]) >= 0 ? toInteger(results[1]) : undefined);
+          const m =     (isString(results[2])       ? results[2] : undefined);
+          const y =     (toInteger(results[3]) >= 0 ? toInteger(results[3]) : undefined);
+          const hours = (toInteger(results[4]) >= 0 ? toInteger(results[4]) : undefined);
+          const mins =  (toInteger(results[5]) >= 0 ? toInteger(results[5]) : undefined);
           metadata.date = new Date(`${m}-${d}, ${y} ${hours}:${mins}:00`);
 
-          metadata.size = toInteger(results[6]) || undefined;
+          metadata.size = (isNumber(toInteger(results[6])) ? toInteger(results[6]) : undefined);
 
           return metadata;
         },
       }
 
-      async function getLinksFromFrame(frame, baseUrl) {
+      const getLinksFromFrame = async (frame, baseUrl) => {
         const server = await getServer(baseUrl) || 'generic';
 
         var query;
@@ -2356,7 +2356,7 @@
         return { server, folders, files };
       }
 
-      async function folderApiRequest(url) {
+      const folderApiRequest = async (url) => {
         const $frame = document.createElement('iframe');
         $frame.style.visibility = 'hidden';
         $frame.style.overflow = 'hidden';
@@ -2381,7 +2381,10 @@
 
       const toNumber = (d) => +d;
       const toInteger = (d) => parseInt(d, 10);
-      const isUndefined = (v) => typeof v === 'undefined';
+      const is = (type) => (v) => typeof v === type;
+      const isNumber = is('number');
+      const isString = is('string');
+      const isUndefined = is('undefined');
 
       global.folderApiRequest = folderApiRequest;
     })(this);
@@ -2543,6 +2546,11 @@
         return re.test(haystack);
       };
 
+      const isImage = (url) => {
+        const re = /(?:\/)((?:[^/])+\.(?:png|jpeg|jpg|gif|webp))/gi
+        return re.test(url);
+      }
+
       const isHiddenFileOrFolder = (url) => {
         const reHidden = /\/\..+$/i;
         return url.toString().match(reHidden);
@@ -2589,6 +2597,28 @@
           html += createFolderTemplate(rawUrl, label);
         });
 
+        const removeUrlExtension = (url) => {
+          const re = /^(.*)(?:\.\w+)$/i;
+          const results = re.exec(url);
+
+          if (results.length > 0) return results[1];
+
+          return undefined;
+        }
+
+        const findThumbnail = (videoUrl, files) => {
+          if (!Array.isArray(files)) return undefined;
+          
+          const videoPrefix = removeUrlExtension(videoUrl);
+          
+          const thumbnails = files.filter((file) => isImage(file.url));
+          const thumb = thumbnails.find((file) => {
+            const filePrefix = removeUrlExtension(file.url);
+            return videoPrefix === filePrefix;
+          });
+          return thumb;
+        }
+
         const subtitles = files.filter((file) => isSubtitle(file.url));
         populateSubtitles(subtitles);
 
@@ -2601,8 +2631,10 @@
           const url = decodeURI(rawUrl).replace(base, '');
           const label = urlToLabel(url);
           const cssClasses = (rawUrl === $player.src ? 'current' : '');
-
-          html += createFileTemplate(rawUrl, label, cssClasses);
+          const preRenderedThumbnail = findThumbnail(file.url, links.files);
+          const thumbnailUrl = (preRenderedThumbnail && preRenderedThumbnail.url ? preRenderedThumbnail.url : '');
+          
+          html += createFileTemplate(rawUrl, label, cssClasses, thumbnailUrl);
         });
 
         $('.links').innerHTML = html;
@@ -2637,8 +2669,8 @@
         updateHash();
       }
 
-      const createFileTemplate = (url, label, optionalClasses = '') => {
-        return `<a href='${url}' class='file ${optionalClasses}' draggable='false'>
+      const createFileTemplate = (url, label, optionalClasses = '', preRenderedThumbnailUrl = '' ) => {
+        return `<a href='${url}' class='file ${optionalClasses}' style='${(preRenderedThumbnailUrl ? '--image-url-0: url(' + preRenderedThumbnailUrl + ')': '')}' draggable='false'>
                   <div class='title' draggable='false'>${label}</div>
                   <div class='arrow' draggable='false'>
                     <svg><use xlink:href='#svg-play'/></svg>
@@ -3752,7 +3784,10 @@
         !$player.ended
       );
 
+      const hasPreRenderedThumbnail = (node) => node.style.getPropertyValue('--image-url-0').length > ('url(http://)').length;
+
       const setThumbnail = async (node, url) => {
+        if (hasPreRenderedThumbnail(node)) return;
         const thumbnailOpts = app.options.thumbnails;
 
         const timestamps = (retrieveSetting('animate') ? [...thumbnailOpts.timestamps] : [thumbnailOpts.timestamps[0]]);
diff --git a/videos/prerendered-thumbnail-gif.gif b/videos/prerendered-thumbnail-gif.gif
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diff --git a/videos/prerendered-thumbnail-gif.mp4 b/videos/prerendered-thumbnail-gif.mp4
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diff --git a/videos/prerendered-thumbnail-jpeg.jpeg b/videos/prerendered-thumbnail-jpeg.jpeg
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diff --git a/videos/prerendered-thumbnail-jpeg.mp4 b/videos/prerendered-thumbnail-jpeg.mp4
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diff --git a/videos/prerendered-thumbnail-png.mp4 b/videos/prerendered-thumbnail-png.mp4
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diff --git a/videos/prerendered-thumbnail-webp.mp4 b/videos/prerendered-thumbnail-webp.mp4
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diff --git a/videos/prerendered-thumbnail-webp.webp b/videos/prerendered-thumbnail-webp.webp
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