YouTube Watch Thumbnails A browser extension that displays YouTube video thumbnail images directly on the watch page, making it easy to view and check all available thumbnail sizes. Features

Automatic Thumbnail Display: Automatically displays thumbnail images next to the channel icon on YouTube watch pages
Hover Zoom: Hover over the thumbnail to see an enlarged preview (1.75x scale)
Thumbnail View Page: Click the thumbnail to open a dedicated page showing all available thumbnail resolutions (WebP and JPG formats)
Multiple Resolutions: View thumbnails in various sizes including maxresdefault, hq720, sddefault, and more
Image Size Information: See the actual dimensions (width × height) of each thumbnail image

How It Works When you visit a YouTube video page, the extension automatically: 1. Detects the video ID from the URL 2. Displays the thumbnail image next to the channel icon 3. Allows you to hover to zoom or click to view all sizes The extension works on: - Regular watch pages (/watch?v=) - YouTube Shorts pages (/shorts/) - All YouTube subdomains (www.youtube.com, m.youtube.com, etc.) Privacy This extension does not collect, store, or transmit any user data. All operations are performed locally in your browser. The extension only accesses YouTube pages to display thumbnail images. Technical Details

Built with React and TypeScript
Uses WXT framework for cross-browser compatibility
No external API calls or data collection
Open source and transparent

mosunset

Published Firefox add-on:

Youtube Watch Thumbnails