If it was real...
If I saw something unusual in the sky, and had my camera ready, I'd take picture after picture, different angles, video (hopefully no sky cam, as is the norm). If there was something legitimately in the sky there, having different photos to compare, to give depth and context would help the case that they saw something.
Otherwise, you have a single photo, proving...there's something in the sky.
Maybe somewhere there's the original, larger size, so one could analyze the picture to make sure there's no photoshopping. Google Image search says no, but. Maybe somewhere there's more info on where it was taken, time, something.
But for now, the OP pegged it. We don't know. I guess it will remain a UFO.