Black cigar-shaped UFO over Cascais, Portugal

On May 30, 2012, a witness shot a black cigar-shaped UFO over Cascais, Portugal. This weird object was only visible on picture.

Witness statement:

I was taking pictures of this fortress called Forte do Guincho, near Cascais, Lisbon.

I didn't notice the object untill I saw the picture. I took one in the same place less than a minute before and another a minute after and the object does not appear in any of these (before and after).

When I saw it (in the picture) I thought of a cigar shape UFO.

I only can describe it as something clear cigar shape, very high in the sky, grey.

I would like to know what can it be...a plane, an UFO? What do you think about it?

Thank you.

Source, 27th February 2018