Python 3.1.1 (r311:74543, Aug 24 2009, 18:44:04) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "copyright", "credits" or "license()" for more information.
>>> ================================ RESTART ================================
>>> 
>>> kk = FileImage('knight.gif')
>>> show(kk)
>>> show(pixelMapper(kk,negativePixel))
>>> show(pixelMapper(kk,grayPixel))
>>>