diff --git a/index.php b/index.php
index 10ad1ca..f7dc92a 100644
--- a/index.php
+++ b/index.php
@@ -682,6 +682,86 @@ $imageHistory = $sessionManager->getImageHistory();
             padding: 30px;
             font-style: italic;
         }
+
+        /* Lightbox Modal */
+        .lightbox-modal {
+            display: none;
+            position: fixed;
+            z-index: 9999;
+            left: 0;
+            top: 0;
+            width: 100%;
+            height: 100%;
+            background-color: rgba(0, 0, 0, 0.95);
+            animation: fadeIn 0.3s;
+        }
+
+        .lightbox-modal.show {
+            display: flex;
+            align-items: center;
+            justify-content: center;
+        }
+
+        .lightbox-content {
+            position: relative;
+            max-width: 95%;
+            max-height: 95%;
+            animation: zoomIn 0.3s;
+        }
+
+        .lightbox-content img {
+            max-width: 100%;
+            max-height: 95vh;
+            display: block;
+            border-radius: 8px;
+            box-shadow: 0 10px 50px rgba(0, 0, 0, 0.8);
+        }
+
+        .lightbox-close {
+            position: absolute;
+            top: 20px;
+            right: 30px;
+            color: #fff;
+            font-size: 40px;
+            font-weight: bold;
+            cursor: pointer;
+            z-index: 10000;
+            transition: all 0.3s;
+            background: rgba(0, 0, 0, 0.5);
+            width: 50px;
+            height: 50px;
+            border-radius: 50%;
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            line-height: 1;
+        }
+
+        .lightbox-close:hover {
+            background: #FFC407;
+            color: #000;
+        }
+
+        @keyframes zoomIn {
+            from {
+                transform: scale(0.8);
+                opacity: 0;
+            }
+            to {
+                transform: scale(1);
+                opacity: 1;
+            }
+        }
+
+        /* Make main image clickable */
+        #currentImage {
+            cursor: pointer;
+            transition: transform 0.3s;
+        }
+
+        #currentImage:hover {
+            transform: scale(1.02);
+        }
     </style>
 </head>
 <body>
@@ -1020,6 +1100,14 @@ Session Directory: <?php echo basename($sessionManager->getSessionDir()); ?></pr
         </div>
     </div>
 
+    <!-- Lightbox Modal -->
+    <div id="lightboxModal" class="lightbox-modal" onclick="closeLightbox(event)">
+        <span class="lightbox-close" onclick="closeLightbox(event)">&times;</span>
+        <div class="lightbox-content">
+            <img id="lightboxImage" src="" alt="Full size image">
+        </div>
+    </div>
+
     <script>
         const form = document.getElementById('imageForm');
         const generateBtn = document.getElementById('generateBtn');
@@ -1153,6 +1241,47 @@ Session Directory: <?php echo basename($sessionManager->getSessionDir()); ?></pr
             link.click();
         }
 
+        // Lightbox functionality
+        function openLightbox(imageSrc) {
+            const modal = document.getElementById('lightboxModal');
+            const lightboxImg = document.getElementById('lightboxImage');
+            lightboxImg.src = imageSrc;
+            modal.classList.add('show');
+            document.body.style.overflow = 'hidden'; // Prevent scrolling
+        }
+
+        function closeLightbox(event) {
+            // Close if clicking on the modal background or close button
+            if (event.target.id === 'lightboxModal' || event.target.className === 'lightbox-close') {
+                const modal = document.getElementById('lightboxModal');
+                modal.classList.remove('show');
+                document.body.style.overflow = 'auto'; // Restore scrolling
+            }
+        }
+
+        // Add click event to main image
+        <?php if ($currentImage): ?>
+        document.addEventListener('DOMContentLoaded', function() {
+            const currentImg = document.getElementById('currentImage');
+            if (currentImg) {
+                currentImg.addEventListener('click', function() {
+                    openLightbox(this.src);
+                });
+            }
+        });
+        <?php endif; ?>
+
+        // Close lightbox with Escape key
+        document.addEventListener('keydown', function(event) {
+            if (event.key === 'Escape') {
+                const modal = document.getElementById('lightboxModal');
+                if (modal.classList.contains('show')) {
+                    modal.classList.remove('show');
+                    document.body.style.overflow = 'auto';
+                }
+            }
+        });
+
         function showError(message) {
             errorMessage.textContent = message;
             errorMessage.classList.add('show');
