Thanks to my great-aunt Ruth, I have a picture of my maternal grandfather, John H. Ufkes (1917-2003) and his parents. My great-grandmother Tena Ufkes (1895-1986, actually born Trientje Janssen) and Fred Ufkes (1893-1960) are also pictured.
Granddad looks to be about 3 or 4, which would make the picture taken around 1920. The 1920 Census shows the Ufkes family living in Bear Creek Township, Hancock County, Illinois, on a rental farm---the farm was actually rented from Fred's father Johann Ufkes (1838-1924).
Don't neglect to contact all family members who might have pictures. And if they are nice enough to share with you, don't forget to send a thank you note.