This is the comment from John Baker of UGS on the same question from UG BBSnotes: "That is not supported (officially or UN-officially) at the moment."
"Wildfires are dangerous, hard to control, and economically catastrophic."
In NX2 you can place a tif or jpg image in a drawing, but the UG plotter functionality cannot print/plot it. Anything older than NX2, no, you cannot...