Once you have imported your new terrain into Sims 2, close the game.
Take a screenshot of the neighbourhood terrain in SimCity 4, centred and zoomed so that the city completely fills the screen. (Use Control and PrintScreen).
Paste into a new file in your graphics editor and crop to a 4 by 3 ratio, or to the pixel size 300x225. Save in Ping (.png) format.
Now name the file to match the Neighbourhood number - so if this city is Rocky Canyon and it is your fourth neighbourhood, the files for it will be in the directory My Documents\EA Games\The Sims 2\Neighborhoods\N004.
In this case rename the picture N004_Neighborhood.png. Now save it in the neighbourhood's directory.
You should now see a still picture of the Neighbourhood in your game when you look at the select a Neighbourhood screen.
The other thing is that you can take pics and add them to the SC4 Terrains folder in the The Sims 2 folder. By naming them after the .SC4 file and add _lush or _desert (with NL also _dirt and _concrete) they will show up instead of that ugly green grid pic.
In this way you´ll end up with 1 SC4 file and 5 PNG´s :
NeighborhoodTerrain.sc4
NeighborhoodTerrain.png
NeighborhoodTerrain_lush.png
NeighborhoodTerrain_desert.png
NeighborhoodTerrain_dirt.png
NeighborhoodTerrain_concrete.png
This tutorial was made by Sita with some input from Rose of 
...
thanks, Rose!