My German grandmother, Hildegard Koenig Paul, future journalist. I have her portable Erika typewriter. My cousin Veronica Stolt has translated the back caption for me.
Veronica writes: "I asked my mother [Birgit Stolt] about the scribblings on the back of the picture of Hildegard in front of the wallpaper. It says, "Ich in meinem goldgelben Biedermeier zu unserm Maskenball 1919," which means "Me in my golden yellow Biedermeier for our Masquerade Ball, 1919." (Biedermeier was a style that developed right before the industrial revolution.) My mother is puzzled by the comment 'Robert' and 'Morgan Koenig.'"
Now that I know the dress is in yellow, I wish even more that the photo were in color. You can read more about Hildegard here.