This image was made by the Curiosity Rover. To see more, click here. The object does not appear to be a video dropout. It is something in the Martian sky. There are probably many ways to dismiss it, but the fact remains that if this was a photo taken of something in Earth's atmosphere, it would be assumed to be a plane with a short contrail. Conceivably, it's a meteor, but it could also be an unknown.