Update kai.md

Author: pliang279

src/content/people/kai.md

@@ -1,6 +1,6 @@
 ---
 name: "Kaichen Zhou"
 title: "Postdoc researcher"
-avatar: "https://kaichen-z.github.io/images/me.jpg"
+avatar: "./images/kaichen.png"
 website: "https://kaichen-z.github.io/"
 ---