Howto Extract PNG from binary file @ 0x80?

[Robert Kern]

Don't seek to position 97. Seek to 96. You're off by one. That's why 
there's the test for the header (which you removed).

Files (and Python strings for that matter) are 0-indexed. The first 
character is 0, the second 1, and so on. If you want the 97th character, 
you have to seek to position 96.

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
  Are the graves of dreams allowed to die."
   -- Richard Harter