Update README.md

CarGuo · web-flow · commit 2ee0722bcd8b · 2020-06-26T17:36:25.000+08:00
diff --git a/README.md b/README.md
@@ -141,7 +141,7 @@
 
 ![](./theme.gif)
 
-<img src="http://img.cdn.guoshuyu.cn/showapp1.png" width="426px"/>
+<img src="http://img.cdn.guoshuyu.cn/showapp1.jpg" width="426px"/>
 
 <img src="http://img.cdn.guoshuyu.cn/showapp2.jpg" width="426px"/>
 
