I have this great story for you. It involves an old photograph and its twin.
My great-great-great-grandfather was Peder Erickson Stedje, born 1824 in Norway, came to Wisconsin in 1871 or so. We came to the United States he changed his last name to Foss.
Very recently I was looking at an old photo album that's belongd to the Foss family. It now belongs to my dad. Sadly most of the pictures are not labeled as to who they are.
One of the photographs was a couple probably in their 60's. The picture had been taken in a photography studio in Norway. I had a couple of guesses as to who they were but no way of knowing for certain.
I had uploaded my dad's DNA test to myheritage. And today I was looking at a DNA match and from the tree attached I can see the person who took the test was from Norway. The person was descended from the brother of my ancestor, Erick Erickson Stedje. Unlike Peter, Erick had stayed in Norway.. there was even a picture attached of Erik Erikson Stedje and his wife. I was looking at it and thought it looked familiar.
I then realized why, it was the exact same picture of the couple from my dad's photo album. Now I knew who they were. The one my dad had was the copy that Erik had sent his brother peder.
I would never have known for sure who those people were if not for the fact, that across the ocean someone had a different copy of it. And put it in their family tree.