I'm  useing  Photoshop to make a gray scale image of a terrain that I am then importing in the terrain editor to make a body of land. What I get is my land has a waffeled appearence.

I made a gray scale image in Photoshop, 500 x 500 pixels at 300 dpi. I then painted a subtle image and then gave it a gaussian blur of 30 to smooth it out and saved is as a jpeg. When I took it over to Vista Pro 4 it comes out looking waffely. Not what I was looking for. How can I fix it? I tried saving it as a bmp and a Tif with same results.