It may depend on whether or not you have Texture Filtering on (at least in Poser 6) - that will give fugly deams, not only at the neck but elsewhere on the model. In some cases it also depends on your texture resolution, I know of a few models that will show seams if you render them with lower resolution than the texture is. But bought textures should be seamless or you should be eglible for a refund.

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You just can't put the words "Poserites" and "happy" in the same sentence - didn't you know that? LaurieA
  Using Poser since 2002. Currently at Version 11.1 - Win 10.