Our Family Trees. This is version: 2023-Apr-26

Thoughts on who the baby is (isn't).
David Beck 2015-02-17:
One of the two photos is dated 1934-03-11. So the photos are two months
before Ignaz dies. Margit and Alfred have been married a year.

It isn't Ilse or Elfi:
Ilse is born in 1929. She too old.
Elfi is born in 1933-05, she would be ten months old. The baby is clearly older.
Besides: The likelihood that Margit, and Alfred are visiting Alfred's grandparents with Margit's niece (from a different city) is extremely unlikely.
I asked Ilse. She doesn't recognize the baby.

The guess of a Kubin child:
The Kubins and the Steins are not relatives. Kubin is the Father's side of Alfred's family. The Stein's are from Alfred's mother's side. Seems unlikely they would be together at all, and if so - there would be adult Kubins too.

The higher likelihood is that this is a great-grand-child of Ignaz & Henriette. They have three children Emma, Max and Julie. Maybe the child in the picture is a grandchild of Emma or Max.