> I encounter problems with the solution below. My test case
> from yesterday was really not a 'test case' because both
> images had near identical values. Thus, the auto vmin,vmax
> settings were the same in both images.
I think the difference we are seeing may due to the fact that the norm
attributes are not set until the figure is drawn. So in a script with
interactive off, the vmin and vmax attrs are not updated from None to
their True values. You can fix this either by working in interactive
mode or by forcing a draw
from pylab import imshow, draw, rand, show
im = imshow(rand(10,10))
print im.norm.vmin, im.norm.vmax
Try the script above with draw commented and uncommented.