Texture Importing With "Shading Scale"

I have a material with a texture attached. Look at it closely. The PNG texture looks very smooth, however the material in Unity appears to have a "shading scale" affect across it.

The object does not appear smoothed out. Can you help me? Thanks.

In-Unity:

In Paint.NET:

UPDATE: I've tried applying multiple blur effects to the image in my image editing software, but with no luck. I get the same effect. Maybe this has something to do with the compression? My texture is set to Billiniar, Automatic Compression. I have tried different compression levels, but still get the same problem.

UPDATE 2: Ok, now I think the problem has to do with lighting, or maybe the quality level?:

Without real time lighting in Unity editor:

with real time lighting:

EDIT: Relevant: http://answers.unity3d.com/questions/45656/light-looks-weird.html