No title
```javascript
// Import the necessary libraries.
const puppeteer = require('puppeteer');
const fs = require('fs');
// Define the function to download the thumbnail.
async function downloadThumbnail(url, outputPath) {
// Create a new Puppeteer browser instance.
const browser = await puppeteer.launch();
// Create a new Puppeteer page.
const page = await browser.newPage();
// Navigate to the given URL.
await page.goto(url);
// Wait for the page to load completely.
await page.waitForSelector('body');
// Get the thumbnail URL from the page.
const thumbnailURL = await page.$eval('meta[property="og:image"]', (element) => element.getAttribute('content'));
// Download the thumbnail.
const response = await page.goto(thumbnailURL);
// Save the thumbnail to the given output path.
fs.writeFileSync(outputPath, await response.buffer());
// Close the Puppeteer browser instance.
await browser.close();
}
// Example usage.
downloadThumbnail('https://www.youtube.com/watch?v=dQw4w9WgXcQ', 'thumbnail.jpg');
```
