```javascript
import { Client, Avatars, Theme, Timezone, BrowserPermission, ImageFormat } from "appwrite";

const client = new Client()
    .setEndpoint('https://<REGION>.cloud.appwrite.io/v1') // Your API Endpoint
    .setProject('<YOUR_PROJECT_ID>'); // Your project ID

const avatars = new Avatars(client);

const result = avatars.getScreenshot({
    url: 'https://example.com',
    headers: {
        "Authorization": "Bearer token123",
        "X-Custom-Header": "value"
    }, // optional
    viewportWidth: 1920, // optional
    viewportHeight: 1080, // optional
    scale: 2, // optional
    theme: Theme.Dark, // optional
    userAgent: 'Mozilla/5.0 (iPhone; CPU iPhone OS 14_0 like Mac OS X) AppleWebKit/605.1.15', // optional
    fullpage: true, // optional
    locale: 'en-US', // optional
    timezone: Timezone.AmericaNewYork, // optional
    latitude: 37.7749, // optional
    longitude: -122.4194, // optional
    accuracy: 100, // optional
    touch: true, // optional
    permissions: [BrowserPermission.Geolocation, BrowserPermission.Notifications], // optional
    sleep: 3, // optional
    width: 800, // optional
    height: 600, // optional
    quality: 85, // optional
    output: ImageFormat.Jpeg // optional
});

console.log(result);
```