Send a message to the person who requested a photo of the grave monument of Edwin Johnson with the following comment:
I'm doing my genealogy and I'm trying to fill in the details. I'll record your site for a source and I understand about not being thanked as it has happen to me. It is for this reason I always try to thank everyone who has helped me and so thank you in advance for the photo (I may ask for more, so thanks for all the help you are willing to give).