A biker snapped a flying saucer in Tennessee

On May 16, 2015, a person drove with a group of motorcyclists near Tellico Plains (Tennessee, USA). He has taken a photo of this event. But, later, he has noticed a black flying saucer on it. What is it?

Witness report:

Our riding group had just pulled off onto Brushy Ridge overlook which is at an elevation of 3750 feet above sea level. No object was seen by any of the people present, including myself. No planes were heard during the incident, no birds were seen as i was taking the photographs. It wasnt until later when i was looking at the photographs that i observed the object in the sky, the object was not visible in any of the other photographs that i had taken while at that location. I took probably 50 shots during the time of the incident. There is one other photograph which was taken in a southerly direction in which a black object is seen in the distance, but i was not able to enlarge the photograph without distortion to tell if it is the same object. That photograph would have been taken before the photograph with the clearly defined object and would have been in the proper time sequence if the object were moving in an easterly direction. I have spoken with others who were present at the time of the incident and no one else reported seeing anything unusual, however, all of them would have been facing the opposite direction during the time of the incident to have seen it, except for one other person who would have been facing the southerly direction as the object was to his southeast direction.