Update people.yml

Author: Jina-Kim

_data/people.yml

@@ -76,7 +76,7 @@ worker:
     profile: Graduate Student <br> UMN CS&E
     link: https://www.linkedin.com/in/ula663312/
   - name: Sarah Wood
-    image: images/people/sarah.png
+    image: images/people/sarah.jpeg
     profile: Undergraduate Student <br> UMN CS&E
     link: https://www.linkedin.com/in/sarah-wood-02a053276/