Attached Link: http://www.keindesign.de/stefan/poser/probelight.html

There is a very good explanation at the attached link. Quick guide to ProbeLight gratification: create a PL node, plug your image map into the PL surface color and plug the PL into the alternate diffuse node. Set the diffuse value of the main PoserSurface to 0. Set PL Saturation to 0, and the exposure to somewhere between 4 and 8, set the PL surface color swatch to white. . Switch off all lights in your scene and test render. Experiment with low intensity lights if you want shadows.