diff --git a/src/Lexicons/App/Bsky/Embed/External.php b/src/Lexicons/App/Bsky/Embed/External.php
index 2e0d91b..4441851 100644
--- a/src/Lexicons/App/Bsky/Embed/External.php
+++ b/src/Lexicons/App/Bsky/Embed/External.php
@@ -101,7 +101,7 @@ public function jsonSerialize(): array
                 'uri' => $this->uri,
                 'title' => $this->title,
                 'description' => $this->description,
-                'blob' => ($b = $this->blob) ? $b : null,
+                'thumb' => ($b = $this->blob) ? $b : null,
             ])
         ];
     }
diff --git a/tests/Feature/Lexicons/Com/Atproto/Repo/CreateRecordTest.php b/tests/Feature/Lexicons/Com/Atproto/Repo/CreateRecordTest.php
index c017835..86da8fc 100644
--- a/tests/Feature/Lexicons/Com/Atproto/Repo/CreateRecordTest.php
+++ b/tests/Feature/Lexicons/Com/Atproto/Repo/CreateRecordTest.php
@@ -125,4 +125,36 @@ public function testPostCreationWithoutBlobUploading(): void
 
         $this->assertIsString($createdRecord->uri());
     }
+
+    public function testPostCreationWithPreviewCard(): void
+    {
+        $client = static::$client;
+
+        $uploadedBlob = $client->com()->atproto()->repo()->uploadBlob()->forge()
+            ->token($client->authenticated()->accessJwt())
+            ->blob(__DIR__.'/../../../../../../art/logo-small.webp')
+            ->send()
+            ->blob();
+
+        $external = $client->app()->bsky()->embed()->external()->forge(
+            'https://shahmal1yev.dev',
+            'Eldar Shahmaliyev\'s blog',
+            'A personal blog about cybersecurity and development.'
+        )->thumb($uploadedBlob);
+
+        $post = $client->app()->bsky()->feed()->post()->forge()
+            ->text('Come to my blog: ')
+            ->link('https://shahmal1yev.dev', 'click here and read the posts')
+            ->embed($external);
+
+        $createRecord = $client->com()->atproto()->repo()->createRecord()->forge()
+            ->record($post)
+            ->repo($client->authenticated()->did())
+            ->collection($post->nsid())
+        ;
+
+        $serializedCreateRecord = json_decode($createRecord, true);
+
+        $this->assertIsArray(Arr::get($serializedCreateRecord, 'record.embed.external.thumb'));
+    }
 }
diff --git a/tests/Unit/Lexicons/App/Bsky/Embed/ExternalTest.php b/tests/Unit/Lexicons/App/Bsky/Embed/ExternalTest.php
index 71757ea..aa4f942 100644
--- a/tests/Unit/Lexicons/App/Bsky/Embed/ExternalTest.php
+++ b/tests/Unit/Lexicons/App/Bsky/Embed/ExternalTest.php
@@ -128,7 +128,7 @@ public function testJsonSerializeWithSetBlob(): void
                 'uri' => 'https://shahmal1yev.dev',
                 'title' => 'foo',
                 'description' => 'bar',
-                'blob' => $this->blob->jsonSerialize()
+                'thumb' => $this->blob->jsonSerialize()
             ],
         ];