Specifying the rock.
I don't know which rock you mean either and I am curious to see which one it is. It's very easy to specify it. Use a ruler and give the position in fractional terms of the image dimensions. For example, ".35 of the way up from the bottom" and ".45 of the way from the left."
Jms, is among the most polite of the posters on this board. Politeness should be returned in kind.
Seems like a good policy in general.
Bob Clark