update preview

README.md

@@ -1,18 +1,20 @@
 # leanote-ios
 
+<a href="https://itunes.apple.com/cn/app/leanote/id1022302858?mt=8" title="Download From App Store" class="ios-download">
+    <img style="width: 200px;" src="http://app.leanote.com/images/ios/apple-store-logo.png" alt="Download From App Store">
+</a>
+
 Coming soon!
 
 ![](./preview/login.png)
 &nbsp;
 ![](./preview/register.png)
-![](./preview/notes.png)
+![](./preview/note.jpeg)
 &nbsp;
-![](./preview/note.png)
+![](./preview/post.jpeg)
-![](./preview/editor.png)
+![](./preview/editor.jpeg)
 &nbsp;
-![](./preview/me.png)
+![](./preview/cate.jpeg)
-![](./preview/notebook.png)
+![](./preview/me.jpeg)
-&nbsp;
-![](./preview/tag.png)
 
 Join us: leanote@leanote.com