Ok...a friend of a friend of a friend gave me a texture. He took it from a poser model texture folder. It works really well as a people putty skin. Let's say I put said skin on a character and then offered it here on this forum. Am I looking at trouble? I own people putty.
Unless you were trying to sell it, i wouldnt worry about posting something you made/changed.
As for textures, whos to say a jpg of skin is from poser or where it came from.[;)]
Besides those skins on those actors are used in all kinds of pictures/paintings/posters with no worry of copyright infringment.