You can do whatever post work you want. Assemble the rendered images in a graphic program, paint things in, erase things, use plugins, blend modes...anything you want.  There are many in the gallery that render a bare image and post work everthing else (hair, clothing, props, background, shadows, lights, softened, blurred etc)

Here are some tutorials to get you started:

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=720&_m=d

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=727&_m=d

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=683&_m=d

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=762&_m=d

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=681&_m=d

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=682&_m=d

http://www.daz3d.com/i.x/tutorial/tutorial/-/?id=762&_m=d

http://www.daz3d.com/i.x/tutorial/0/-/

Here are some galleries where the artist typically does a great deal of post work. There are others, but these are the few that come to mind:

http://www.renderosity.com/mod/gallery/browse.php?username=addy

http://www.renderosity.com/mod/gallery/browse.php?username=prog

http://www.renderosity.com/mod/gallery/browse.php?username=antje

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi