It looked fine when I started playing, aside from having a green, hilly grid for a preview picture. Still has that.
I'm not sure if this is still bothering you, but it's easy to fix - EA even posted on how to fix it:
http://thesims2.ea.com/help/detail.php?help_id=91The important bit:
"Adding a custom neighborhood picture
In order to create a custom picture to represent your neighborhood on the main menu, first save the picture you wish to use as a .png file (a 4x3 size ratio works best, but pictures with other proportions will be stretched to fit).
The file must be named N0XX_Neighborhood.png (where XX is the neighborhood number). Then place the file in the neighborhood's directory (e.g., My Documents\EA Games\The Sims 2\Neighborhoods\N004)."
(You could put a picture of anything there, and it still shows up as your neighbourhood preview picture.)