and why its so important!

I don’t know for sure who took this photo. It has to be one of two people. The two women in front of me ( me with the green coat and pink hat) are walking companions from the US. The person next to me appears to be a mystery pilgrim. And the two other walking companions were behind us. One of them took the photo, but each of them think it was her shot.
I did as much detective work as I could. I found the photo is each person’s photo stream. I saw that the photo was taken with a iPhone 5, which both of them were using.
I searched through all the pictures I could find that were taken by any member of this group. I found other pictures of this mystery pilgrim, and none proved her to be without a doubt anyone I knew. I love this picture. I also love both my dear friends who had their iPhone5’s out that day to catch such a marvelous shot. So, not knowing what else to do, they both got the photo credit.
Another friend worked on it to get it up to the parameters of a cover photo. And then I relied on a hired designer to make it look a bit more like a painting than a photo.
What else could I have done to solve this mystery?
Please comment. I love to hear your thoughts!