Just kidding. But perhaps you should read the info on the world editor before asking stupid questions like this? No offense.
There's a nifty tool called the Unit Editor. It's in the top of the World Edit screen, it's the one with the little helmet icon.
Click it, go to the unit you want to edit, look for art - scaling value. Most of the time, this value is set to 1.00, but you can set it to 325084095673958 if you want a unit to take up the entire map. K? Anymore questions?