Hi!
Apparently this bug is in the library i use for importing images.. i could not solve the white line appearing at the edge of the image, but i could solve the hard invert that you see in the normal borders..
This fix will be available in next release. You will still see that annoying white border in the preview, but normals are fine, and you shouldn't notice them ingame.
If i find a way to solve that also i'll let you know.