```css
/* Optimized styles for Mehak Bhatt Escorts */
:root {
    --primary-color: #25D366; /* WhatsApp green */
    --primary-hover: #1ebe57;
    --bg-light: #f4f4f9;
    --shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

body {
    font-family: 'Arial', sans-serif;
    background-color: var(--bg-light);
    margin: 0;
    line-height: 1.6;
}

.hero-bg {
    background: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7)), url('/images/hero-bg.webp') center/cover no-repeat;
    background-size: cover;
    background-position: center;
}

.card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow);
}

.whatsapp-btn {
    background-color: var(--primary-color);
    color: #fff;
    padding: 0.625rem 1.25rem;
    border-radius: 1.5rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: background-color 0.3s ease;
}

.whatsapp-btn:hover {
    background-color: var(--primary-hover);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
    object-fit: cover; /* Ensure images scale properly */
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .hero-bg {
        padding: 4rem 1rem;
    }
    .hero-bg h2 {
        font-size: 2rem;
    }
    .hero-bg p {
        font-size: 1rem;
    }
    .card {
        margin-bottom: 1rem;
    }
    .card img {
        width: 150px; /* Smaller images for mobile */
        height: 150px;
        margin: 0 auto;
    }
}

@media (max-width: 640px) {
    header nav {
        flex-direction: column;
        gap: 0.5rem;
    }
    header nav a {
        font-size: 0.9rem;
    }
}
```

#### CSS Changes
- **No Major Changes**: The existing CSS already supports responsive images with `max-width: 100%`, `height: auto`, and `object-fit: cover`.
- **Mobile Image Sizing**: The `.card img` rule for `max-width: 768px` sets `width: 150px` and `height: 150px` to ensure smaller images on mobile, aligning with `srcset` usage.
- **Centered Images**: Added `margin: 0 auto` to `.card img` for consistent centering on mobile.

---

### Updated `index.html`
<xaiArtifact artifact_id="7b0339d8-c198-42e9-8c03-3fd3c9ae4544" artifact_version_id="aeb438fb-230e-4b51-b6df-4ed40c8052f6" title="index.html" contentType="text/html">
```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Premium Delhi escorts from ₹2999. Book discreet, high-class companions 24/7 via WhatsApp. Cash only, no advance. Call +91-9999180969!">
    <meta name="keywords" content="Delhi escorts, premium escorts, independent escorts, Russian escorts, housewife escorts, air hostess escorts, BDSM services, girlfriend experience, luxury companionship">
    <meta name="author" content="Mehak Bhatt Escorts">
    <meta name="robots" content="index, follow">
    <meta name="google-site-verification" content="QWX9Fg1Xr_12KIysHR-dOKXJkidMkDoQnu7gJITQ02Q" />
    <link rel="canonical" href="https://mehakbhatt.com/">
    <!-- Open Graph Tags -->
    <meta property="og:title" content="Mehak Bhatt Escorts - Premium Delhi Escorts">
    <meta property="og:description" content="Premium Delhi escorts from ₹2999. Book discreet, high-class companions 24/7 via WhatsApp. Cash only, no advance. Call +91-9999180969!">
    <meta property="og:type" content="website">
    <meta property="og:url" content="https://mehakbhatt.com/">
    <meta property="og:image" content="https://mehakbhatt.com/images/og-image.webp">
    <meta property="og:image:width" content="1200">
    <meta property="og:image:height" content="630">
    <!-- Google Analytics -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=G-ZEP5ESNQ9X"></script>
    <script>
        window.dataLayer = window.dataLayer || [];
        function gtag(){dataLayer.push(arguments);}
        gtag('js', new Date());
        gtag('config', 'G-ZEP5ESNQ9X');
    </script>
    <title>Mehak Bhatt Escorts - Premium Delhi Escorts Service</title>
    <link href="https://cdn.jsdelivr.net/npm/tailwindcss@2.2.19/dist/tailwind.min.css" rel="stylesheet">
    <link rel="stylesheet" href="css/style.css">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
</head>
<body>
    <!-- Header -->
    <header class="bg-gray-900 text-white py-4 sticky top-0 z-50 shadow-lg">
        <div class="container mx-auto flex justify-between items-center px-4">
            <h1 class="text-2xl font-bold">Mehak Bhatt Escorts</h1>
            <nav class="space-x-4">
                <a href="index.html" class="hover:text-gray-300">Home</a>
                <a href="about.html" class="hover:text-gray-300">About</a>
                <a href="service.html" class="hover:text-gray-300">Services</a>
                <a href="gallery.html" class="hover:text-gray-300">Gallery</a>
                <a href="rate.html" class="hover:text-gray-300">Rates</a>
                <a href="contact.html" class="hover:text-gray-300">Contact</a>
            </nav>
        </div>
    </header>

    <!-- Hero Section -->
    <section class="hero-bg text-white py-20 text-center">
        <div class="container mx-auto px-4">
            <h2 class="text-4xl md:text-5xl font-bold mb-4">Premium Delhi Escorts Service</h2>
            <p class="text-lg mb-6">Book hot call girls starting at ₹2999 – Cash Payment, No Advance, 24/7 Availability</p>
            <a href="https://wa.me/919999180969" class="whatsapp-btn text-lg"><i class="fab fa-whatsapp mr-2"></i> Book Now via WhatsApp</a>
        </div>
    </section>

    <!-- Services Section -->
    <section id="services" class="py-16 bg-white">
        <div class="container mx-auto px-4">
            <h2 class="text-3xl font-bold text-center mb-12">Our Exclusive Services</h2>
            <div class="grid grid-cols-1 md:grid-cols-3 gap-8">
                <div class="card bg-gray-100 p-6 rounded-lg text-center">
                    <h3 class="text-xl font-semibold mb-2">Independent Escorts</h3>
                    <p>Discreet, sophisticated companions for personalized luxury experiences across Delhi.</p>
                    <a href="service.html" class="text-blue-600 hover:underline">Learn More</a>
                </div>
                <div class="card bg-gray-100 p-6 rounded-lg text-center">
                    <h3 class="text-xl font-semibold mb-2">Russian Escorts</h3>
                    <p>Exotic and charming models for a thrilling night in upscale venues.</p>
                    <a href="service.html" class="text-blue-600 hover:underline">Learn More</a>
                </div>
                <div class="card bg-gray-100 p-6 rounded-lg text-center">
                    <h3 class="text-xl font-semibold mb-2">Housewife Escorts</h3>
                    <p>Curvy, experienced bhabhis offering intimate moments in luxury settings.</p>
                    <a href="service.html" class="text-blue-600 hover:underline">Learn More</a>
                </div>
            </div>
            <div class="text-center mt-8">
                <a href="service.html" class="text-blue-600 hover:underline">Explore All Services</a>
            </div>
        </div>
    </section>

    <!-- Models Section -->
    <section id="models" class="py-16 bg-gray-100">
        <div class="container mx-auto px-4">
            <h2 class="text-3xl font-bold text-center mb-12">Meet Our Models</h2>
            <div class="grid grid-cols-1 md:grid-cols-4 gap-8">
                <div class="card bg-white p-6 rounded-lg text-center">
                    <img src="images/model-priya-200.webp" srcset="images/model-priya-200.webp 200w, images/model-priya-400.webp 400w" sizes="(max-width: 768px) 150px, 200px" alt="Priya – VIP Escort" width="200" height="200" loading="lazy" class="rounded-full mx-auto mb-4">
                    <h3 class="text-xl font-semibold">Priya – VIP Escort</h3>
                    <p>A sophisticated companion for elite experiences in Delhi.</p>
                    <a href="gallery.html" class="text-blue-600 hover:underline">View Profile</a>
                </div>
                <div class="card bg-white p-6 rounded-lg text-center">
                    <img src="images/model-anisha-200.webp" srcset="images/model-anisha-200.webp 200w, images/model-anisha-400.webp 400w" sizes="(max-width: 768px) 150px, 200px" alt="Anisha – College Girl" width="200" height="200" loading="lazy" class="rounded-full mx-auto mb-4">
                    <h3 class="text-xl font-semibold">Anisha – College Girl</h3>
                    <p>A vibrant and youthful companion for fun-filled moments.</p>
                    <a href="gallery.html" class="text-blue-600 hover:underline">View Profile</a>
                </div>
            </div>
            <div class="text-center mt-8">
                <a href="gallery.html" class="text-blue-600 hover:underline">View All Models</a>
            </div>
        </div>
    </section>

    <!-- Footer -->
    <footer class="bg-gray-900 text-white py-8">
        <div class="container mx-auto px-4 text-center">
            <p>Mehak Bhatt Escorts provides companionship services for adults 18+. We operate in compliance with Indian laws.</p>
            <p class="mt-4">Contact: <a href="tel:+919999180969" class="hover:text-gray-300">+91-9999180969</a></p>
            <p class="mt-4">&copy; 2025 Mehak Bhatt Escorts. All rights reserved.</p>
            <div class="mt-4 space-x-4">
                <a href="terms.html" class="hover:text-gray-300">Terms</a>
                <a href="faq.html" class="hover:text-gray-300">FAQ</a>
                <a href="about.html" class="hover:text-gray-300">About</a>
            </div>
        </div>
    </footer>

    <script src="js/script.js"></script>
</body>
</html>
```

#### Changes in `index.html`
1. **Model Images**:
   - Added `srcset` with two resolutions:
     - `images/model-priya-200.webp` (200x200px, <50KB) for standard displays.
     - `images/model-priya-400.webp` (400x400px, <100KB) for high-DPI (retina) displays.
     - Same for `images/model-anisha-200.webp` and `images/model-anisha-400.webp`.
   - Added `sizes="(max-width: 768px) 150px, 200px"` to match the CSS rule (150px on mobile, 200px on desktop).
   - Retained `loading="lazy"`, `width="200"`, `height="200"`, and descriptive `alt` attributes.
2. **Open Graph Image**:
   - Updated `og:image` to `images/og-image.webp` (1200x630px, <100KB).
   - Added `og:image:width` and `og:image:height` for social media compatibility.
   - Note: `srcset` is not supported for `og:image`, so only one image is specified.
3. **No Other Changes**: Preserved meta tags, Google Analytics, and content structure.

---

### Updated `gallery.html`
<xaiArtifact artifact_id="febba82a-fe1f-4aeb-90dd-94ff06c91d83" artifact_version_id="52782fab-86bc-41c2-b72d-73c8fe714379" title="gallery.html" contentType="text/html">
```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Meet our premium Delhi escorts: VIP, Russian, Housewife models. View profiles & book via WhatsApp: +91-9999180969!">
    <meta name="keywords" content="Delhi escorts gallery, escort profiles, premium escorts">
    <meta name="author" content="Mehak Bhatt Escorts">
    <meta name="robots" content="index, follow">
    <meta name="google-site-verification" content="QWX9Fg1Xr_12KIysHR-dOKXJkidMkDoQnu7gJITQ02Q" />
    <link rel="canonical" href="https://mehakbhatt.com/gallery.html">
    <!-- Open Graph Tags -->
    <meta property="og:title" content="Gallery of Premium Delhi Escorts">
    <meta property="og:description" content="Meet our premium Delhi escorts: VIP, Russian, Housewife models. View profiles & book via WhatsApp: +91-9999180969!">
    <meta property="og:type" content="website">
    <meta property="og:url" content="https://mehakbhatt.com/gallery.html">
    <meta property="og:image" content="https://mehakbhatt.com/images/og-image.webp">
    <meta property="og:image:width" content="1200">
    <meta property="og:image:height" content="630">
    <!-- Google Analytics -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=G-ZEP5ESNQ9X"></script>
    <script>
        window.dataLayer = window.dataLayer || [];
        function gtag(){dataLayer.push(arguments);}
        gtag('js', new Date());
        gtag('config', 'G-ZEP5ESNQ9X');
    </script>
    <title>Gallery - Mehak Bhatt Escorts</title>
    <link href="https://cdn.jsdelivr.net/npm/tailwindcss@2.2.19/dist/tailwind.min.css" rel="stylesheet">
    <link rel="stylesheet" href="css/style.css">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
</head>
<body>
    <header class="bg-gray-900 text-white py-4 sticky top-0 z-50 shadow-lg">
        <div class="container mx-auto flex justify-between items-center px-4">
            <h1 class="text-2xl font-bold">Mehak Bhatt Escorts</h1>
            <nav class="space-x-4">
                <a href="index.html" class="hover:text-gray-300">Home</a>
                <a href="about.html" class="hover:text-gray-300">About</a>
                <a href="service.html" class="hover:text-gray-300">Services</a>
                <a href="gallery.html" class="hover:text-gray-300">Gallery</a>
                <a href="rate.html" class="hover:text-gray-300">Rates</a>
                <a href="contact.html" class="hover:text-gray-300">Contact</a>
            </nav>
        </div>
    </header>

    <section class="py-16 bg-gray-100">
        <div class="container mx-auto px-4">
            <h2 class="text-3xl font-bold text-center mb-12">Meet Our Models</h2>
            <div class="grid grid-cols-1 md:grid-cols-4 gap-8">
                <div class="card bg-white p-6 rounded-lg text-center">
                    <img src="images/model-priya-200.webp" srcset="images/model-priya-200.webp 200w, images/model-priya-400.webp 400w" sizes="(max-width: 768px) 150px, 200px" alt="Priya – VIP Escort" width="200" height="200" loading="lazy" class="rounded-full mx-auto mb-4">
                    <h3 class="text-xl font-semibold">Priya – VIP Escort</h3>
                    <p>A sophisticated companion for elite experiences in Delhi.</p>
                </div>
                <div class="card bg-white p-6 rounded-lg text-center">
                    <img src="images/model-anisha-200.webp" srcset="images/model-anisha-200.webp 200w, images/model-anisha-400.webp 400w" sizes="(max-width: 768px) 150px, 200px" alt="Anisha – College Girl" width="200" height="200" loading="lazy" class="rounded-full mx-auto mb-4">
                    <h3 class="text-xl font-semibold">Anisha – College Girl</h3>
                    <p>A vibrant and youthful companion for fun-filled moments.</p>
                </div>
                <div class="card bg-white p-6 rounded-lg text-center">
                    <img src="images/model-sonia-200.webp" srcset="images/model-sonia-200.webp 200w, images/model-sonia-400.webp 400w" sizes="(max-width: 768px) 150px, 200px" alt="Sonia – Russian Model" width="200" height="200" loading="lazy" class="rounded-full mx-auto mb-4">
                    <h3 class="text-xl font-semibold">Sonia – Russian Model</h3>
                    <p>An exotic beauty for a thrilling and luxurious night.</p>
                </div>
                <div class="card bg-white p-6 rounded-lg text-center">
                    <img src="images/model-leela-200.webp" srcset="images/model-leela-200.webp 200w, images/model-leela-400.webp 400w" sizes="(max-width: 768px) 150px, 200px" alt="Leela – Housewife" width="200" height="200" loading="lazy" class="rounded-full mx-auto mb-4">
                    <h3 class="text-xl font-semibold">Leela – Housewife</h3>
                    <p>A charming, experienced bhabhi for intimate encounters.</p>
                </div>
            </div>
        </div>
    </section>

    <footer class="bg-gray-900 text-white py-8">
        <div class="container mx-auto px-4 text-center">
            <p>Mehak Bhatt Escorts provides companionship services for adults 18+. We operate in compliance with Indian laws.</p>
            <p class="mt-4">Contact: <a href="tel:+919999180969" class="hover:text-gray-300">+91-9999180969</a></p>
            <p class="mt-4">&copy; 2025 Mehak Bhatt Escorts. All rights reserved.</p>
            <div class="mt-4 space-x-4">
                <a href="terms.html" class="hover:text-gray-300">Terms</a>
                <a href="faq.html" class="hover:text-gray-300">FAQ</a>
                <a href="about.html" class="hover:text-gray-300">About</a>
            </div>
        </div>
    </footer>

    <script src="js/script.js"></script>
</body>
</html>
```

#### Changes in `gallery.html`
1. **Model Images**:
   - Added `srcset` for each model image:
     - `images/model-[name]-200.webp` (200x200px, <50KB) for standard displays.
     - `images/model-[name]-400.webp` (400x400px, <100KB) for high-DPI displays.
   - Added `sizes="(max-width: 768px) 150px, 200px"` to match CSS (150px on mobile, 200px on desktop).
   - Retained `loading="lazy"`, `width="200"`, `height="200"`, and descriptive `alt` attributes.
2. **Open Graph Image**:
   - Updated `og:image` to `images/og-image.webp` (1200x630px, <100KB).
   - Added `og:image:width` and `og:image:height` for social media compatibility.
3. **No Other Changes**: Preserved meta tags, Google Analytics, and content structure.

---

### Template for Other Pages
Other pages (`about.html`, `service.html`, `rate.html`, `blog.html`, `locations.html`, `contact.html`, `job.html`, `faq.html`, `testimonials.html`, `terms.html`) do not contain `<img>` tags in the provided content, so only their `og:image` needs updating for consistency. Below is the updated `<head>` template:

```html
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="[Page-specific description]">
    <meta name="keywords" content="[Page-specific keywords]">
    <meta name="author" content="Mehak Bhatt Escorts">
    <meta name="robots" content="index, follow">
    <meta name="google-site-verification" content="QWX9Fg1Xr_12KIysHR-dOKXJkidMkDoQnu7gJITQ02Q" />
    <link rel="canonical" href="https://mehakbhatt.com/[page].html">
    <!-- Open Graph Tags -->
    <meta property="og:title" content="[Page-specific OG title]">
    <meta property="og:description" content="[Page-specific OG description]">
    <meta property="og:type" content="website">
    <meta property="og:url" content="https://mehakbhatt.com/[page].html">
    <meta property="og:image" content="https://mehakbhatt.com/images/og-image.webp">
    <meta property="og:image:width" content="1200">
    <meta property="og:image:height" content="630">
    <!-- Google Analytics -->
    <script async src="https://www.googletagmanager.com/gtag/js?id=G-ZEP5ESNQ9X"></script>
    <script>
        window.dataLayer = window.dataLayer || [];
        function gtag(){dataLayer.push(arguments);}
        gtag('js', new Date());
        gtag('config', 'G-ZEP5ESNQ9X');
    </script>
    <title>[Page Title] - Mehak Bhatt Escorts</title>
    <link href="https://cdn.jsdelivr.net/npm/tailwindcss@2.2.19/dist/tailwind.min.css" rel="stylesheet">
    <link rel="stylesheet" href="css/style.css">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.4.0/css/all.min.css">
</head>
```

Replace `[Page-specific description]`, `[Page-specific keywords]`, `[page].html`, `[Page-specific OG title]`, `[Page-specific OG description]`, and `[Page Title]` with the values from previous responses.

---

### Image Preparation Recommendations
1. **Image Resolutions**:
   - **Model Images**:
     - Low-res: `images/model-[name]-200.webp` (200x200px, <50KB).
     - High-res: `images/model-[name]-400.webp` (400x400px, <100KB).
     - Example: `model-priya-200.webp`, `model-priya-400.webp`, etc.
   - **Open Graph Image**: `images/og-image.webp` (1200x630px, <100KB).
   - **Hero Background**: `images/hero-bg.webp` (1920x1080px, <200KB).
2. **Compression**:
   - Use tools like Squoosh, TinyPNG, or ImageOptim to convert images to WebP and compress them.
   - Ensure quality is balanced with file size (e.g., 80% quality for WebP).
3. **File Naming**:
   - Use descriptive names (e.g., `model-priya-200.webp`) for SEO and organization.
   - Store all images in the `images/` folder.
4. **Privacy**: As per the original document, ensure model images are blurred or anonymized for privacy compliance.

---

### Summary of Changes
- **HTML Updates**:
  - Added `srcset` and `sizes` to model images in `index.html` and `gallery.html` for responsive loading.
  - Updated `og:image` to `images/og-image.webp` with `og:image:width` and `og:image:height` across all pages.
  - Retained `loading="lazy"`, `width`, `height`, and descriptive `alt` attributes.
- **CSS Updates**:
  - Ensured `.card img` supports responsive sizing (150px on mobile, 200px on desktop) to align with `sizes` attribute.
  - Added `margin: 0 auto` for centered images on mobile.
- **No Changes to Other Files**:
  - `script.js`, `sitemap.xml`, and `robots.txt` remain unchanged.
- **Performance Benefits**:
  - **Responsive Images**: `srcset` allows browsers to select smaller images for low-resolution or mobile devices, reducing bandwidth usage.
  - **Lazy Loading**: Combined with `loading="lazy"`, minimizes initial page load time.
  - **CLS Prevention**: Explicit `width` and `height` attributes prevent layout shifts.
  - **WebP Format**: Smaller file sizes improve load speed, especially on mobile.

---

### Notes
1. **Testing**:
   - Use Chrome DevTools (Network tab) to verify that browsers select the correct image from `srcset` based on device resolution and viewport size.
   - Test lazy loading by scrolling through `index.html` and `gallery.html` to ensure images load only when visible.
   - Check CLS in Lighthouse (aim for CLS <0.1) and social media sharing (e.g., Facebook Sharing Debugger) for `og:image`.
2. **Image Preparation**:
   - Create two versions of each model image (200x200px and 400x400px) in WebP format using Squoosh or TinyPNG.
   - Upload to `images/` folder: `model-priya-200.webp`, `model-priya-400.webp`, etc., and `og-image.webp`.
3. **Deployment**:
   - Upload updated HTML and CSS files to your server.
   - Ensure the `images/` folder contains all WebP images.
   - Clear cache and verify HTTPS to avoid mixed content issues.
4. **Further Enhancements**:
   - Add more resolutions to `srcset` (e.g., 100px for very small screens) if needed.
   - Implement a picture element for art direction (e.g., different images for mobile vs. desktop) if design requirements change.
   - Use a CDN (e.g., Cloudflare) to cache images for faster delivery.

If you need the full updated HTML for all pages, assistance with image conversion, or additional optimizations (e.g., picture element, CDN setup), let me know!