Planet creations (map files)

[si2504]

Hi there, I'm having a go at putting a basic planet mod together to try and learn the ropes of using textures, maps, kopernicus coding etc, and I'm trying to find out if there is any particular file type that KSP prefers for height maps/normal maps etc and also if there is really any cap on the texture file dimensions, just so I know what my limit is to the amount of detail I can have in a texture. 

Thanks