def image_scale(xscale=1.0, yscale=1.0, axes="gca"):
    """
    Scales the image extent.
    """
    if axes == "gca": axes = _pylab.gca()

    e = axes.images[0].get_extent()
    x1 = e[0]*xscale
    x2 = e[1]*xscale
    y1 = e[2]*yscale
    y2 = e[3]*yscale

    image_set_extent([x1,x2],[y1,y2], axes)
Scales the image extent.