showing an image on log axes?

One can control the aspect ratio with Axes.set_aspect(), so

    > making a new figure is not really necessary now.

Fernando, if you haven't played with the new aspect handling courtesy
of Mark Bakkar and Eric, you should give it a whirl in your freetime

As Eric indicates, it "just works" now, under the presence of figure
resizes, etc. Thus some changes in matshow are warranted.