Matplotlib PNGs by default has a nice white background.
> What if you want to put the PNGs in a blue web page?
> Is there a way to make PNGs inherit background colors of
> web pages?
You can set the alpha property of any matplotlib figure element. The
two entities of interest here are the figure patch (rectangle
background) and axes patch (ditto)
#0 is transparent, 1 is opaque