Do you mean the sides outside or inside the map? (if that makes sense)
Outside. The inside Map is fine, and the outside Graphic is nice, its just that its filling up 1/3rd of the Screen maybe.
I had an idea about changing the background depending on where you are and then what you hover over. What do you think?
I'd have to see it in Action. But the Background Image isn't really the Problem, the current one is good. Its that theres so much empty Space while at the same Time requiring you to scroll up through the Map so far.