diff --git a/src/manifest.json b/src/manifest.json
index 05beea4..6e7ac70 100644
--- a/src/manifest.json
+++ b/src/manifest.json
@@ -1,7 +1,7 @@
 {
   "manifest_version": 3,
   "name": "__MSG_extName__",
-  "version": "3.0.1",
+  "version": "3.0.2",
   "description": "__MSG_extDescription__",
   "default_locale": "en",
   "permissions": ["contextMenus"],
diff --git a/src/viewer/error.js b/src/viewer/error.js
index 133469c..b9594b5 100644
--- a/src/viewer/error.js
+++ b/src/viewer/error.js
@@ -7,4 +7,9 @@ export function showError(error) {
   $('error-details').textContent = error.toString();
   $('error').classList.remove('hidden');
   $('nav').classList.add('hidden');
+
+  const [firefox, version] = navigator.userAgent.match(/Firefox\/(\d+)/) ?? [];
+  if (firefox != null && Number(version) < 127) {
+    $('error-firefox').classList.remove('hidden');
+  }
 }
diff --git a/src/viewer/gallery.js b/src/viewer/gallery.js
index 3571efd..e5125a7 100644
--- a/src/viewer/gallery.js
+++ b/src/viewer/gallery.js
@@ -1,16 +1,24 @@
 import { $, $e } from './utils.js';
 
+/**
+ * @param {string} url
+ * @returns {string}
+ */
+function getCaption(url) {
+  const [, mediaType] = url.match(/data:(.+?)[,;]/) ?? [];
+  return mediaType ?? url;
+}
+
 /**
  * @param {string[]} images
  */
 export function setupGallery(images) {
   const figures = images.map((image) => {
-    const caption = image.startsWith('data:image/svg+xml') ? 'SVG' : image;
     return $e(
       'figure',
       {},
       $e('a', { href: image }, $e('img', { src: image })),
-      $e('figcaption', {}, caption),
+      $e('figcaption', {}, getCaption(image)),
     );
   });
 
diff --git a/src/viewer/index.html b/src/viewer/index.html
index 629743d..5b10204 100644
--- a/src/viewer/index.html
+++ b/src/viewer/index.html
@@ -28,6 +28,16 @@ <h1 id="error-message"></h1>
       <ul>
         <li id="error-reload"></li>
         <li id="error-security"></li>
+        <li id="error-firefox" class="hidden">
+          Open about:addons and enable Permissions &gt; Access your data for all
+          websites. <br />
+          <a
+            href="https://discourse.mozilla.org/t/content-scripts-do-not-load/130009"
+            target="_blank"
+          >
+            Please see this issue for more details.
+          </a>
+        </li>
       </ul>
       <p id="error-details"></p>
       <p>