Update courses-cn.html

Author: riverfor

docs/courses-cn.html

@@ -33,7 +33,7 @@ <h2 class="text-xl font-bold text-center">QPython使用介绍</h2>
 
             <!-- Image 3 -->
             <a href="#" onclick="milib.openUrl('https://mp.weixin.qq.com/s/UVpkhDtnL-00CpgS11PkWg')" class="block bg-white rounded-lg shadow-lg overflow-hidden">
-                <img src="https://edu.qpython.org/static/xingqiu.png" alt="QPython知识星球" class="w-full">
+                <img src="https://edu.qpython.org/static/zhishi.png" alt="QPython知识星球" class="w-full">
                 <div class="p-4">
                     <h2 class="text-xl font-bold text-center">QPython知识星球</h2>
                 </div>