Ancestor Photos

Great Grandfather-- what rank?

I am afraid I have lost the history of my mothers side of the family. I don't even know his name but the young girl is my ommi Annalisa. I think the photo was taken in 1937 or 38 but not sure. I think I was told that he retired before the fighting broke out. He was a calvery man in the great war as I have two small unit flags from his outfit. Please help-- Rank? Unit? When?-- any info will be helpful. Thanks