Update README-cn.md

Author: aidlearning

README-cn.md

@@ -103,7 +103,7 @@ AI编程平台由深度学习框架和Python可视化编程框架（Python IDE
 - [更多示例](http://code.aidlearning.net)
 
 
-<img src="https://www.aidlearning.net/git_img/aid-examples.png" height="1024"/>
+<img src="https://www.aidlearning.net/git_img/aid-examples.jpg" height="1024"/>
 
 <img src="https://cdn.nlark.com/yuque/0/2020/png/726405/1588573935881-54e2a362-57f2-4afb-9312-a5ccd2355ecf.png"/>