You wrote your great grandmother was Wallner from Zell am See
I know the Photoatelier Leopold Haidinger (He was photographer around 1880 - 1900 then his son Carl run the atelier and now Karl Haidinger still runs the Atelier.
Your great grandmother grew up two houses far from our house.
My grandgrandfather had around 1900 a shop in the house of the wallner family.
This house now belongs to Mrs.Fischer Hertha (Her mother was
a daughter of the Wallner - she married a Buchner.)
Maybe Mrs. Fischer could help you.
Hertha Caroline Fischer, Seegasse 12, A 5700 Zell am See
Tel.: 0043 6542 72636
Best regards - Hermann Schmiderer