MARGARET (Maggie) MCGREGOR CAMPBELL AND MR CAMPBELL

Seeking information on a “Mr and Mrs. Campbell (Maggie McGregor)” whose photo appears on pg 638 of “They Came to Mara…”
I have been unsuccessful in identifying “Mr. Campbell”.
I would love to know when and where the Campbells were married, where they lived after their marriage, whether they had children, etc.
The photo in the book was courtesy of Mary Wither who contributed quite a number of the photos in the book. I wonder whether there might there be any way of determining who contributed the McGregor information.

I would be most grateful for any assistance.