I tried to port my new worldmap in my mod folder and it doesn't work (neither .Png nor .Sti). The interface folder contains a new interface and it works. Also, I did some .xml editing and that works too.
I doubled checked the naming convention and it's good.
I see that different mods can have a different number of worldmaps in different resolutions: Can I make with it with a single image?


EDIT: It was a matter or image format, it must be .Pcx.