"If these are just for your own use, you don't need to worry about anything; you can raid other texture files all you like, modify them any way you please, just so long as you don't distribute the result, and just use it in your own renders." That's fine... but it isn't going to be good enough for me. We make a substantial part of our income doing 3D work for clients, and that includes custom designed characters for use in corporate identity. It woudl be nice to sell them a texture directly instead of adding it to the list of things they have to buy (they already need to buy a seperate copy of the meshes we use as a base for instance).