Terrain Tileset Question

[Swiftblaze]

Is there any way to change the tileset of an existing map or add more types of tiles to a tileset for a map?

Also, do I need a unique Reign of Chaos CD-Key as well as a unique Frozen Throne CD-Key to play on battle.net or can I just use a different Frozen Throne key but the same Reign of Chaos key as a friend's?

 

[esb]

Yes, Modify Tileset. There is a limit though (16 "Slots) and some tiles take up 2 "slots", some take 1. Some are not editable (meaning you cannot remove/add, usually cliffs).

Maximum is... 16 I think, unless you do another program like WEU (Not recommended)

 

[Black Hawk]

Yes as esb said Modify Tilset. Each tile takes an amount shown as a big number taking most of the icons space. But if you want to know where it is, it is found at Advanced > Modify Tileset.