diff --git a/Output.php b/Output.php
index 197858b..913db25 100644
--- a/Output.php
+++ b/Output.php
@@ -83,7 +83,7 @@ class Output
 
         /** @var \Doku_Renderer_xhtml $renderer */
         $renderer = $this->renderer;
-        $renderer->doc .= '<div class="luxtools-plugin luxtools-gallery">';
+        $renderer->doc .= '<div class="luxtools-plugin luxtools-gallery" data-luxtools-gallery="1">';
 
         foreach ($this->files as $item) {
             $url = $this->itemWebUrl($item, !empty($params['randlinks']));
@@ -98,6 +98,10 @@ class Output
             $safeThumbUrl = hsc($thumbUrl);
             $safePlaceholderUrl = hsc($placeholderUrl);
             $label = hsc($item['name']);
+            $caption = hsc(basename((string)($item['name'] ?? '')));
+            if ($caption === '') {
+                $caption = $label;
+            }
 
             $initialSrc = $safePlaceholderUrl;
                 $dataThumb = ' data-thumb-src="' . $safeThumbUrl . '"';
@@ -108,7 +112,14 @@ class Output
                 $dataThumb = '';
             }
 
-            $renderer->doc .= '<a href="' . $safeUrl . '" class="media" title="' . $label . '" aria-label="' . $label . '">';
+            $renderer->doc .= '<a'
+                . ' href="' . $safeUrl . '"'
+                . ' class="media luxtools-gallery-item"'
+                . ' title="' . $label . '"'
+                . ' aria-label="' . $label . '"'
+                . ' data-luxtools-full="' . $safeUrl . '"'
+                . ' data-luxtools-name="' . $caption . '"'
+                . '>';
             $renderer->doc .= '<img'
                 . ' class="luxtools-thumb"'
                 . ' src="' . $initialSrc . '"'
@@ -119,6 +130,7 @@ class Output
                 . ' loading="lazy"'
                 . ' decoding="async"'
                 . ' />';
+            $renderer->doc .= '<span class="luxtools-gallery-caption">' . $caption . '</span>';
             $renderer->doc .= '</a>';
         }
 
diff --git a/script.js b/script.js
index acc5e59..e7acb8f 100644
--- a/script.js
+++ b/script.js
@@ -43,6 +43,171 @@
     }
   }
 
+  function ensureLightbox() {
+    var existing = document.querySelector('.luxtools-lightbox');
+    if (existing) return existing;
+
+    var root = document.createElement('div');
+    root.className = 'luxtools-lightbox';
+    root.setAttribute('role', 'dialog');
+    root.setAttribute('aria-modal', 'true');
+    root.setAttribute('aria-hidden', 'true');
+
+    root.innerHTML =
+      '<div class="luxtools-lightbox-backdrop" data-luxtools-action="close"></div>' +
+      '<div class="luxtools-lightbox-stage">' +
+        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-close" data-luxtools-action="close" aria-label="Close">×</button>' +
+        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-prev" data-luxtools-action="prev" aria-label="Previous">‹</button>' +
+        '<img class="luxtools-lightbox-img" alt="" />' +
+        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-next" data-luxtools-action="next" aria-label="Next">›</button>' +
+        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-opennew" data-luxtools-action="newtab" aria-label="Open in new tab">↗</button>' +
+        '<div class="luxtools-lightbox-caption"></div>' +
+      '</div>';
+
+    document.body.appendChild(root);
+    return root;
+  }
+
+  function getGalleryItems(galleryEl) {
+    var links = galleryEl.querySelectorAll('a.luxtools-gallery-item[data-luxtools-full]');
+    var items = [];
+    links.forEach(function (a) {
+      var full = a.getAttribute('data-luxtools-full') || a.getAttribute('href') || '';
+      var name = a.getAttribute('data-luxtools-name') || a.getAttribute('title') || '';
+      if (!full) return;
+      items.push({ el: a, full: full, name: name });
+    });
+    return items;
+  }
+
+  function openLightboxFor(galleryEl, startEl) {
+    var items = getGalleryItems(galleryEl);
+    if (!items.length) return;
+
+    var index = 0;
+    for (var i = 0; i < items.length; i++) {
+      if (items[i].el === startEl) { index = i; break; }
+    }
+
+    var lb = ensureLightbox();
+    var img = lb.querySelector('img.luxtools-lightbox-img');
+    var cap = lb.querySelector('.luxtools-lightbox-caption');
+
+    var pushedHistory = false;
+    var closingFromPopstate = false;
+
+    function clamp(n) {
+      if (n < 0) return items.length - 1;
+      if (n >= items.length) return 0;
+      return n;
+    }
+
+    function render() {
+      var it = items[index];
+      img.src = it.full;
+      img.setAttribute('data-luxtools-index', String(index));
+      cap.textContent = (it.name || '').trim();
+    }
+
+    function openInNewTab() {
+      var it = items[index];
+      if (!it || !it.full) return;
+      try {
+        window.open(it.full, '_blank', 'noopener');
+      } catch (e) {
+        // ignore
+      }
+    }
+
+    function close() {
+      lb.classList.remove('is-open');
+      lb.setAttribute('aria-hidden', 'true');
+      try { document.documentElement.classList.remove('luxtools-noscroll'); } catch (e) {}
+      try { document.body.style.overflow = ''; } catch (e) {}
+      // Clear src to stop downloads on close.
+      img.src = '';
+      document.removeEventListener('keydown', onKeyDown, true);
+      window.removeEventListener('popstate', onPopState, true);
+
+      // If we opened by pushing a state, pop it when closing via UI.
+      if (pushedHistory && !closingFromPopstate) {
+        try {
+          if (window.history && window.history.state && window.history.state.luxtoolsLightbox === 1) {
+            window.history.back();
+          }
+        } catch (e) {
+          // ignore
+        }
+      }
+    }
+
+    function next() {
+      index = clamp(index + 1);
+      render();
+    }
+
+    function prev() {
+      index = clamp(index - 1);
+      render();
+    }
+
+    function onKeyDown(e) {
+      if (!lb.classList.contains('is-open')) return;
+      var key = e.key || '';
+      if (key === 'Escape') {
+        e.preventDefault();
+        close();
+      } else if (key === 'ArrowRight') {
+        e.preventDefault();
+        next();
+      } else if (key === 'ArrowLeft') {
+        e.preventDefault();
+        prev();
+      }
+    }
+
+    function onPopState() {
+      if (!lb.classList.contains('is-open')) return;
+      closingFromPopstate = true;
+      try { close(); } finally { closingFromPopstate = false; }
+    }
+
+    lb.onclick = function (e) {
+      var t = e.target;
+      if (!t || !t.getAttribute) return;
+      var action = t.getAttribute('data-luxtools-action') || '';
+      if (action === 'close') { e.preventDefault(); close(); }
+      if (action === 'next') { e.preventDefault(); next(); }
+      if (action === 'prev') { e.preventDefault(); prev(); }
+      if (action === 'newtab') { e.preventDefault(); openInNewTab(); }
+
+      // Click outside the image closes (but don't interfere with controls).
+      if (t.closest && t.closest('button.luxtools-lightbox-btn')) return;
+      if (t.closest && t.closest('img.luxtools-lightbox-img')) return;
+      e.preventDefault();
+      close();
+    };
+
+    // Open
+    lb.classList.add('is-open');
+    lb.setAttribute('aria-hidden', 'false');
+    try { document.documentElement.classList.add('luxtools-noscroll'); } catch (e) {}
+    try { document.body.style.overflow = 'hidden'; } catch (e) {}
+    document.addEventListener('keydown', onKeyDown, true);
+    window.addEventListener('popstate', onPopState, true);
+
+    // Allow closing via browser back button.
+    try {
+      if (window.history && window.history.pushState) {
+        window.history.pushState({ luxtoolsLightbox: 1 }, '', window.location.href);
+        pushedHistory = true;
+      }
+    } catch (e) {
+      // ignore
+    }
+    render();
+  }
+
   function getServiceUrl(el) {
     var url = el.getAttribute('data-service-url') || '';
     url = (url || '').trim();
@@ -128,7 +293,27 @@
     return null;
   }
 
+  function findGalleryItem(target) {
+    var el = target;
+    while (el && el !== document) {
+      if (el.classList && el.classList.contains('luxtools-gallery-item')) return el;
+      el = el.parentNode;
+    }
+    return null;
+  }
+
   function onClick(event) {
+    // Image gallery lightbox: intercept clicks so we don't navigate away.
+    var galleryItem = findGalleryItem(event.target);
+    if (galleryItem) {
+      var gallery = galleryItem.closest ? galleryItem.closest('div.luxtools-gallery[data-luxtools-gallery="1"]') : null;
+      if (gallery) {
+        event.preventDefault();
+        openLightboxFor(gallery, galleryItem);
+        return;
+      }
+    }
+
     var el = findOpenElement(event.target);
     if (!el) return;
 
diff --git a/style.css b/style.css
index 637bfd8..06434ae 100644
--- a/style.css
+++ b/style.css
@@ -52,9 +52,161 @@ div.luxtools-plugin .luxtools-empty {
 /* Image gallery spacing. */
 div.luxtools-gallery {
     padding-bottom: 0.5em;
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.35em;
 }
 
-div.luxtools-gallery a.media {
+div.luxtools-gallery a.media.luxtools-gallery-item {
     display: inline-block;
-    margin: 0 0.35em 0.35em 0;
+    position: relative;
+    border: 1px solid @ini_border;
+    background-color: @ini_background_alt;
+    overflow: hidden;
+    line-height: 0;
+    text-decoration: none;
+}
+
+div.luxtools-gallery a.media.luxtools-gallery-item:hover,
+div.luxtools-gallery a.media.luxtools-gallery-item:focus {
+    border-color: @ini_text;
+}
+
+div.luxtools-gallery img.luxtools-thumb {
+    display: block;
+    width: 150px;
+    height: 150px;
+    object-fit: cover;
+}
+
+/* Filename overlay (single line, muted). */
+div.luxtools-gallery .luxtools-gallery-caption {
+    position: absolute;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    font-size: 0.75em;
+    line-height: 1.3;
+    padding: 0.25em 0.4em;
+    color: #fff;
+    background: rgba(0, 0, 0, 0.35);
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    pointer-events: none;
+}
+
+/* Disable background scrolling while the lightbox is open. */
+html.luxtools-noscroll,
+html.luxtools-noscroll body {
+    overflow: hidden !important;
+}
+
+/* Fullscreen lightbox viewer (client-side). */
+.luxtools-lightbox {
+    position: fixed;
+    inset: 0;
+    z-index: 9999;
+    display: none;
+}
+
+.luxtools-lightbox.is-open {
+    display: block;
+}
+
+.luxtools-lightbox .luxtools-lightbox-backdrop {
+    position: absolute;
+    inset: 0;
+    background: rgba(0, 0, 0, 0.85);
+}
+
+.luxtools-lightbox .luxtools-lightbox-stage {
+    position: absolute;
+    inset: 0;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    padding: 0.8em;
+}
+
+.luxtools-lightbox img.luxtools-lightbox-img {
+    max-width: 100%;
+    max-height: 100%;
+}
+
+.luxtools-lightbox .luxtools-lightbox-caption {
+    position: absolute;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    padding: 0.6em 1em;
+    color: #fff;
+    opacity: 0.9;
+    background: rgba(0, 0, 0, 0.35);
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    text-align: center;
+}
+
+/* Top-left "open in new tab" button. */
+.luxtools-lightbox button.luxtools-lightbox-opennew {
+    left: 0.6em;
+    top: 0.6em;
+    bottom: auto;
+    width: 2.4em;
+    height: 2.4em;
+    background: transparent;
+    border: none;
+    border-radius: 0.2em;
+    z-index: 2;
+}
+
+
+.luxtools-lightbox button.luxtools-lightbox-btn {
+    position: absolute;
+    cursor: pointer;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    color: #fff;
+}
+
+/* Navigation: transparent left/right tap zones (default everywhere). */
+.luxtools-lightbox button.luxtools-lightbox-prev,
+.luxtools-lightbox button.luxtools-lightbox-next {
+    top: 0;
+    bottom: 0;
+    width: 30%;
+    background: transparent;
+    border: none;
+    padding: 0;
+    font-size: 2em;
+    color: rgba(255, 255, 255, 0.7);
+}
+
+.luxtools-lightbox button.luxtools-lightbox-prev {
+    left: 0;
+}
+
+.luxtools-lightbox button.luxtools-lightbox-next {
+    right: 0;
+}
+
+/* Close button overlays content. */
+.luxtools-lightbox button.luxtools-lightbox-close {
+    top: 0.6em;
+    right: 0.6em;
+    width: 2.2em;
+    height: 2.2em;
+    background: transparent;
+    border: none;
+    z-index: 2;
+}
+
+@media (max-width: 600px) {
+    .luxtools-lightbox button.luxtools-lightbox-prev,
+    .luxtools-lightbox button.luxtools-lightbox-next {
+        font-size: 1.6em;
+    }
 }