HeightMap generated on the Terrain. Mirroring error

HeightMap generated on the Terrain. Mirroring error

I just mastered the skills HeightMap.

The use of photoshop cs4 produced HeightMap.

But now discovered a problem. Terrain to produce and do not meet HeightMap.'s Like a mirror.

105626--4041--$error_953.jpg

Dont confused by your eyes, just conside the different coordinate.For the picture the top left point is the origin.Generating terrain needs a loop to get all point in the heightmap