(click image for larger view)

If you import the image as a 'Background Picture', then that's exactly what you get, a background picture that is not moveable. If you want to be able to move it, you should load it into a Poser 'One Sided Square' primitive as an image map.  If you want part of the image to to be transparent, then you can use a transparency map plugged into the Transparency node. A transparency map  is an image where the parts you want to be transparent are absolute black, and the parts you want to be opaque are absolute white, shades of grey give various degrees of transparency.