Weird object snapped near Helena, Montana

On June 4, 2014, while he was on vacation in Helena (state of Montana), a tourist has taken multiple photos of landscapes. A few months later, by watching these pictures, he has noticed an unusual shaped in the sky. What is it?

Witness statement:

I was on vacation in Montana in June 2014. I took some photos with my iPhone at Spring Meadow Lake State Park in Helena, MT. I then downloaded them to my computer. I was looking at the pictures recently on my computer and I noticed a black dot in the middle of the clouds in the one horizontal photo. When I zoomed in it looked like an oval shaped object. The weird thing is that I have another photo that I took vertically directly after taking the first one and that black object is not in the photo. I also have some more photos of the area before and after and I don't see any objects in the sky. While I was actually there on vacation, I didn't notice the object. At the time I did not notice this object; I just noticed it today when I was deleting old photos on my computer.