Terrain gets cut off when importing height map, Please help!

So I can't find an answer for what I'm doing wrong and I'm getting too frustrated trying to figure it out on my own. I'm trying in import in a heightmap and the map gets cut off every time. I made the image resolution 513X513 like your suppose too and changed between bit-8, and bit-16 still no good. I also made sure it was in grayscale and not RBG and imported in as a raw. I get a few errors w$$anonymous$$le importing in the heightmap so that's probably related to the issue. Also, I use Gimp to edit the resolution and etc if that helps. I would appreciate the help if anyone can spare the time.

Error: EndLayoutGroup: BeginLayoutGroup must be called first. UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Original Heightmap jpeg file.