Sorry if this one has been answered.

I am trying to use a black and white image to create a terrain, copying the image to clipboard out of photoshop and pasting in the "image" tab in terrains. The original image is a square. I started out at 750 x 750 then tried 500 x 500 and even went down to 250 x 250....every time I paste it does some odd, off center, tiling thing.
Is there some new default setting I am missing?
This is useless to me if I can't get the image to paste correctly.