Update README.md

README.md

@@ -11,6 +11,6 @@ pinned: false
 
 Hi! 👋
 
-This is an unofficial organization of [Xi'an Jiaotong University](http://en.xjtu.edu.cn/), and all interested parties are welcome to join😊.
+This is an ***unofficial*** organization of [Xi'an Jiaotong University](http://en.xjtu.edu.cn/), and all interested people are welcome to join! 😊
 
-<img src="https://vi.xjtu.edu.cn/images/a4-7sbzh.png" width="500" height="500" />
+<img src="https://vi.xjtu.edu.cn/images/a4-7sbzh.png" width="300" height="300" />