In Paint Shop pro, I created the images using 32x32 tiles. The world map is a 6080x2880 image with about 2 dozen layers. To bring it into Gamestudio, I have a PSP script that automatically divides the world map into a bunch of 320x320 images (10 tiles x 10 tiles).

Inside the game, the 320x320 images are created and placed as sprite entities with ent_create. I just have a couple of nested for-loops that line everything up seamlessly.

The town images are simply panels, since I don't need to worry about passable/impassable locations there.