[Matplotlib-users] How to remove white space

[yogesh k. <yog...@gm...>]

Dear All,
               I have one .png image of 940X780 and i am plotting waveforms
on it. When I save this plot as .png , matp[lotlib gives image in
800X600 that too with white space. I dont want to keep the white space and i
want the same resolution as original image.How should I go ahead?
Thanks in advance!!!
Regards
Yogesh