IDENTIFICATION ON PHOTO: "Ethel, Fred & Martha Morrison (neighbors of Delila & A D Johnston)"
PHOTO TAKEN: unknown location and photographer, circa 1918-1920
PURCHASED: Jun 2021, Springfield, OR, Antique Peddlers
Because this is a postcard photo, there is not the usual photographic studio stamp with which to determine a location where these children resided.
I thought this might have been taken around 1910, but the back of the card features an AZO stamp box with triangles at the corners, pointing up on top and down on bottom. This dates the postcard from 1918 or later. That will be a useful clue.
This will take some serious research!