Not a problem. Just take that greyscale and run the Contrast adjustment on it (second or third menu from the left, I think). Run it all the way. Or, if you are a little more daring, use the Levels adjustment instead and bring the black and white points towards the middle. That way, you can adjust just how big the "holes" are. Save this the thing as an 8-bit JPG -- it'll be close enough for Poser to deal with it.