My problem is that when I try to resize the image, I'm given a choice of inches, mm, or pixels per inch. 700 pixels per inch means the image is still too large, whereas 70 does diminish the clarity. Christine, do you know how many pixels per inch it should be.
In the meantime, I've done a close-up that might be slightly more informative regarding the mottling effect.
Here's a much better one.