Studio Spirits?

We find these photos very neat! This picture was taken at a photo studio in Tombstone. After looking at these photos, I took a walk around the area and found nothing that could have created the strange light above the pictures, The other photos that she took had nothing strange.

Now if you look at the first picture you'll see the light at the top as well as, what looks to be a shadow covering all of the girls. Then as the pictures continue the light moves to the right.