python - How to make pylab.savefig () saves the image as a maximize window instead of the default size

I am using pylab in matplotlib to create a plot and save the plot to an image file. However, when I save the image using pylab.savefig( image_name ), I find that the SIZE image saved is the same as the image that is shown when I use pylab.show().

As it happens, I have a lot of data in the plot and when I am using pylab.show(), I have to maximize the window before I can see all of the plot correctly, and the xlabel tickers don't superimpose on each other.

Is there anyway that I can programmatically 'maximize' the window before saving the image to file? - at the moment, I am only getting the 'default' window size image, which results in the x axis labels being superimposed on one another.