Making copy of image.

How can I copy one Blender image into the other, without them being bound to the same data?

I tried image.copy() and image.deepcopy(). This does not work.

Current workaround: saving and reloading the image…
Not very elegant…

How about

image_new = image_old.__copy__()

error:

AttributeError: ‘Blender Image’ object has no attribute ‘copy