There's a difference between a 3D Image, and a 3D figure...There is really not much a thing as a 3D image.  Poser can Render your image, but you need to start with someone else's human, and then Sculpt away everything that does not look like the human you want.

To start from scratch, with Vertex 0, you need a Modeler application, like that which has been listed.  Some a free, others are moderate(Carrara is like Poser) other are very expensive $1000-$4000+.