read part of jpeg file by pure python

[Pacino]

Hi, everyone,

I am wondering whether it's possible to read part (e.g. 1000*1000) of
a huge jpeg file (e.g. 30000*30000) and save it to another jpeg file
by pure python. I failed to read the whole file and split it, because
it would cost 2GB memory.

Can anyone help me? Any comments would be appreciated.

Thanks.

Robert