While I usually save as .png and merge over a background image in photoshop, you can get some VERY good results rendering over a background in Poser itself so I wouldn't necessarily give up on it.

http://www.renderosity.com/mod/gallery/index.php?image_id=1639105

This image is pure poser (7sr2) with the sole exception of adjusting the contrast and adding the border/signature in photoshop.  The hard part is setting up the lights to match the background.

i7 6800 (6 core/12 thread), 24 GB RAM, 1 gtx 1080 ti (8GB Vram) + 1 Titan X (12GB Vram), PP11, Octane/Poser plugin, and a partridge in a pear tree.

Oh, and a wiener dog!