Update index.md

Author: fhyuancn

docs/index.md

@@ -430,8 +430,8 @@ Each approach offers unique strengths:
     [ESIIL staff edit in Markdown](https://github.com/CU-ESIIL/Summit_group_2026_14/edit/main/docs/index.md?plain=1#L28){ .md-button target="_blank" rel="noopener" }
 
 
-![Team hero image](assets/hero/hero.png)
 ![Team hero image](assets/hero/hero2.png)
+![Team hero image](assets/hero/hero.png)
 
 !!! note "How to replace the image above"
     Upload an image that represents your project and welcome people to your page.