- images are displayed within their native dtype range,
- unless they are outside of their range (e.g. a float image with
values greater than 1) or they are of an unsupported dtype (e.g.
a uint64 image), in which case the dynamic range of the display
corresponds to the image range,
- which is also done for images with extremely low contrast for their
native range (e.g. float images in [1e-7, 5e-7].
In the latter two cases, a colorbar is also displayed and a warning is
raised.
Finally, we return the axes object on which the image is plotted, to
enable further plotting in the matplotlib new OO style.