when using the GD backed, you can write directly to a
> stream (in your case could be sys.stdout).. the same
> functionality has not been implemented for agg yet (last
> time i checked).. i needed this before, and hacked it up
> for GD in the early days (didn't even have agg back
> then).. i think it would be great to have this implemented
> for agg, but i think noone got around to doing it yet...
Finally I did - long overdue. The agg backend now will print png to
a file object, including sys.stdout.
Give it a whirl...