diff --git a/frontend/src/components/ImageLightbox.css b/frontend/src/components/ImageLightbox.css
index 8ae60eb..d08dac9 100644
--- a/frontend/src/components/ImageLightbox.css
+++ b/frontend/src/components/ImageLightbox.css
@@ -16,3 +16,35 @@
   object-fit: contain;
   border-radius: var(--radius);
 }
+
+.image-lightbox-actions {
+  position: absolute;
+  top: var(--sp-4);
+  right: var(--sp-4);
+  z-index: 1;
+  display: flex;
+  gap: 6px;
+  cursor: default;
+}
+
+.image-lightbox-download,
+.image-lightbox-close {
+  width: 32px;
+  height: 32px;
+  border-radius: var(--radius);
+  background: rgba(0, 0, 0, 0.5);
+  border: 1px solid rgba(255, 255, 255, 0.2);
+  color: #fff;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  cursor: pointer;
+  font-size: 1.1rem;
+  line-height: 1;
+}
+
+.image-lightbox-download:hover,
+.image-lightbox-close:hover {
+  background: rgba(0, 0, 0, 0.7);
+  border-color: rgba(255, 255, 255, 0.4);
+}
diff --git a/frontend/src/components/ImageLightbox.tsx b/frontend/src/components/ImageLightbox.tsx
index 5248642..d027ddb 100644
--- a/frontend/src/components/ImageLightbox.tsx
+++ b/frontend/src/components/ImageLightbox.tsx
@@ -11,6 +11,26 @@ export function ImageLightbox({ src, onClose }: ImageLightboxProps) {
 
   return (
     <div className="image-lightbox" onClick={onClose}>
+      <div className="image-lightbox-actions" onClick={(e) => e.stopPropagation()}>
+        {/* Bare `download` (no explicit filename) -- MessageImage doesn't
+            store an original filename, but the server response's own
+            Content-Type header is enough for the browser to infer a
+            sensible extension on its own. */}
+        <a href={src} download className="image-lightbox-download" aria-label="Download">
+          <svg width="15" height="15" viewBox="0 0 20 20" fill="none" aria-hidden="true">
+            <path
+              d="M10 3v10m0 0-4-4m4 4 4-4M4 16h12"
+              stroke="currentColor"
+              strokeWidth="1.6"
+              strokeLinecap="round"
+              strokeLinejoin="round"
+            />
+          </svg>
+        </a>
+        <button type="button" className="image-lightbox-close" onClick={onClose} aria-label="Close">
+          ×
+        </button>
+      </div>
       <img src={src} alt="" className="image-lightbox-img" />
     </div>
   )