Use displacement with the grayscale image instaed of Bump or gradient bump map. Displacement will offer the greater realism. In this throen together example Iv added wrinkles and a scar to the standard DAZ V3 grayscale image. Notice her ear is distorted. Thats cuz of the noise in the grayscale image that suppose to rsemble skin pores. Its probably better to just leave that area of the grayscale image solid white