[Image-SIG] Newbie bug

[Edward C. Jones]

I am new at PIL. The following program gave an error. What to do?

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Traceback (innermost last):
  File "./thresh.py", line 17, in ?
    outim = im.point(lut, im.mode)
  File "/usr/lib/python1.5/site-packages/PIL/Image.py", line 525,
in point
    im = self.im.point(lut, mode)
ValueError: Images do not match

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#! /usr/bin/python

import Image, sys, string

if len(sys.argv) != 4:
        raise 'must have exactly three parameters'
t = string.atoi(sys.argv[1])
im = Image.open(sys.argv[2])

lut = (3*256) * [0]

for i in range(t,256):
        lut[i] = 1
        lut[i+256] = 1
        lut[i+512] = 1

outim = im.point(lut, im.mode)
outim.save(sys.argv[3])