diff --git a/object/user.go b/object/user.go
index 76fd2899..62f0efe9 100644
--- a/object/user.go
+++ b/object/user.go
@@ -96,6 +96,10 @@ func GetUser(id string) *User {
 }
 
 func GetMaskedUser(user *User) *User {
+	if user == nil {
+		return nil
+	}
+
 	if user.Password != "" {
 		user.Password = "***"
 	}
diff --git a/web/public/favicon.png b/web/public/favicon.png
deleted file mode 100644
index 9c0b1564..00000000
Binary files a/web/public/favicon.png and /dev/null differ
diff --git a/web/public/index.html b/web/public/index.html
index dc710d18..46b808b2 100644
--- a/web/public/index.html
+++ b/web/public/index.html
@@ -9,12 +9,12 @@
       name="description"
       content="Web site created using create-react-app"
     />
-    <link rel="apple-touch-icon" href="%PUBLIC_URL%/favicon.png" />
+    <link rel="apple-touch-icon" href="https://cdn.casbin.org/site/casdoor/favicon.png" />
     <!--
       manifest.json provides metadata used when your web app is installed on a
       user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
     -->
-    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <link rel="manifest" href="https://cdn.casbin.org/site/casdoor/manifest.json" />
     <!--
       Notice the use of %PUBLIC_URL% in the tags above.
       It will be replaced with the URL of the `public` folder during the build.
diff --git a/web/public/manifest.json b/web/public/manifest.json
deleted file mode 100644
index d6bb8e0c..00000000
--- a/web/public/manifest.json
+++ /dev/null
@@ -1,15 +0,0 @@
-{
-  "short_name": "Casdoor",
-  "name": "Casdoor Authentication",
-  "icons": [
-    {
-      "src": "favicon.png",
-      "sizes": "64x64 32x32 24x24 16x16",
-      "type": "image/x-icon"
-    }
-  ],
-  "start_url": ".",
-  "display": "standalone",
-  "theme_color": "#000000",
-  "background_color": "#ffffff"
-}
diff --git a/web/src/index.css b/web/src/index.css
index 93a161a5..9d93ff35 100644
--- a/web/src/index.css
+++ b/web/src/index.css
@@ -13,7 +13,7 @@ code {
 }
 
 .logo {
-  background: url("logo.png");
+  background: url("https://cdn.casbin.org/img/logo_384x96.png");
   background-size: 108px, 33px;
   width: 108px;
   height: 27px;
diff --git a/web/src/logo.png b/web/src/logo.png
deleted file mode 100644
index 7e5d1ecf..00000000
Binary files a/web/src/logo.png and /dev/null differ