Change default cover image

Author: CavemanJay

themes/butterfly/_config.yml

@@ -91,8 +91,7 @@ cover:
   # left/right/both
   position: both
   # When cover is not set, the default cover is displayed (當沒有設置cover時，默認的封面顯示)
-  default_cover:
-    - https://dan-feliciano.com/images/cyberpunk-red.jpg
+  default_cover: /images/rocketman.jpg
 
 # Replace Broken Images (替換無法顯示的圖片)
 error_img: