PIL's ImageFile Parser and PNG's

[Silfheed]

Heyas

So I've been messing around with the PIL and PNG's and came across a
little problem with PNG's.

So just to clarify, I'm running with the standard ubuntu 8.04 python-
imaging package that installs zlib and all the other goodies that go
along to make the PIL work with PNG's nicely.

So this works fine:

 from PIL import Image
 x = Image.open('some.png')
 x.show()

But if I try to get  a bit fancier and do
 from PIL import ImageFile
 p = ImageFile.Parser()
 p.feed(open('some.png','rb').read())
 image = p.close()
 image.show()

I get a traceback:
Traceback (most recent call last):
  File "basic_img.py", line 9, in <module>
    image.show()
  File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 1450, in
show
    _showxv(self, title, command)
  File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 2089, in
_showxv
    file = image._dump(format=format)
  File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 477, in
_dump
    self.load()
  File "/usr/lib/python2.5/site-packages/PIL/ImageFile.py", line 189,
in load
    s = read(self.decodermaxblock)
  File "/usr/lib/python2.5/site-packages/PIL/PngImagePlugin.py", line
365, in load_read
    return self.fp.read(bytes)
  File "/usr/lib/python2.5/site-packages/PIL/ImageFile.py", line 300,
in read
    data = self.data[pos:pos+bytes]
TypeError: 'NoneType' object is unsubscriptable

But if all I do is change some.png to some.jpg (or gif), it works
fine.   Am I doing something horribly wrong, or forget to compile
something that was supposed to be compiled for PNG support?  Is it a
known bug with a fix somewhere that I just haven't found (I've
searched all over the PIL site)

Thanks