So this is something that's always bothered me and its a simple question. Whenever I expand my region (I always make them too small) by making the config.bmp bigger, I can only expand in two directions (south and east in game terms) just by the nature of a config.bmp (mine are also solid green since I only build on medium tiles). This means my downtown is always in the top left corner of my eventual region! How can I change this?
The only way to get around that is to make a new region and import your cities one by one.