UFO Sighting in Winder, Georgia on January 2nd 2015 – was taking photo of sun dog. Noticed object in photo above horizon

I was waiting for my son and grandson outside Barrow county Education Administration Building in parking lot. I noticed 3 jet contrails and a sun dog next to one of them. I took a few photos of the sky and found they object in one of the photos 15-20 seconds after taking picture. It was gone when I tried to film it again. I didn't know the object was there until after I took the picture. I never saw it leave. I'm still puzzled. It was not a plane, helicopter, balloon or SWAMP GAS. It's bothered me constantly since I took the picture. I still have it in my phone and computer.