Sorry, I should have quoted more before. Here's a better version. From same link as before.
Interview with Alien Photographer - UFO Evidence
-- What was it about that shot that drew your attention?
--Look, first I took a photo of the Carabinero patrol that was coming over the nearby bridge. Then, since I was riding my bike, I headed for the northern sector. I took another photo of them from that point, and that's the one on the Internet.
--Did you see the alien in the [digital camera's] screen?
--No, I saw it the next day, when I downloaded the photo.
--And what did you think?
--I was impressed, that's all. I saw it with a colleague and we found it odd. I thought that it was the same impression everyone else who saw the photo must have had. It's rather shocking. The fact of the matter is that I didn't see it when I took the picture.
--Do you recall seeing anything odd at the time?
No, nothing at all. And I also asked myself that when I checked the photo, I tried to recall what was there. It would have been ideal to have seen it when the photo was taken, by I saw nothing strange. I was interested in taking a photo of the mounted patrol.
--If it was an alien it should have come out in the other photos you took that day.
--Yes, it could have come out, but it appears in that one only. Now, the other (photos) are from other areas.