adding a logo image to a plot

You can use a combination of axes() to define where you

    > want the image and imshow() to define the image. Use
    > frame_on=False with axes(). You can pass a PIL image
    > directly to imshow(), and that way you won't have to use
    > imread, (although you'd have to use

If your logo is a fixed size in pixels, you can also use figimage to
place an unscaled image directly onto the canvas.

A wiki entry on matplotlib images + PIL would be useful.