diff --git a/beastify/README.md b/beastify/README.md
index 941189a..12fe7a4 100644
--- a/beastify/README.md
+++ b/beastify/README.md
@@ -25,6 +25,7 @@ When the user clicks the reset button, the page reloads, and reverts to its orig
 ## What it shows ##
 
 * write a browser action with a popup
+* how to have different browser_action images based upon the theme
 * give the popup style and behavior using CSS and JS
 * inject a content script programmatically using `tabs.executeScript()`
 * send a message from the main extension to a content script
diff --git a/beastify/icons/beasts-32-light.png b/beastify/icons/beasts-32-light.png
new file mode 100644
index 0000000..dbed714
Binary files /dev/null and b/beastify/icons/beasts-32-light.png differ
diff --git a/beastify/icons/beasts-32.png b/beastify/icons/beasts-32.png
index bcf6379..89863cc 100644
Binary files a/beastify/icons/beasts-32.png and b/beastify/icons/beasts-32.png differ
diff --git a/beastify/manifest.json b/beastify/manifest.json
index e8bf86b..81f8865 100644
--- a/beastify/manifest.json
+++ b/beastify/manifest.json
@@ -11,14 +11,19 @@
 
   "permissions": [
     "activeTab"
-  ],  
+  ],
 
   "browser_action": {
     "default_icon": "icons/beasts-32.png",
+    "theme_icons": [{
+        "light": "icons/beasts-32-light.png",
+        "dark": "icons/beasts-32.png",
+        "size": 32
+    }],
     "default_title": "Beastify",
     "default_popup": "popup/choose_beast.html"
   },
-  
+
   "web_accessible_resources": [
     "beasts/frog.jpg",
     "beasts/turtle.jpg",