Adjusting a background image to a tilemap?

I have a student that used a background image instead of a tilemap and now has some issues with the funtionality of his game. Is it possible to change the background image into a tilemap to address the issues?

https://arcade.makecode.com/S53824-35218-76327-30115

Honestly I don’t really see anything wrong with it…
Could you specify the issues in question?