Hi Julia,
I am not aware of this photo. Guess I need to make a rode trip! The only actual photos I have seen are very scratchy and only show a very disintegrated part of wall taken from a distance. There are a few paintings of what it might have looked like. The fort was supposedly very similar to Bent's Fort in LaJunta. I have also heard that the historic museum in Colorado Springs has a few things about FSV but I haven't been there. Perhaps your post will bring more information from others.