Wow, that is a good photo - I have never seen such a clear shot of a thylacine. Real tragedy (as are all animals driven by people to extinction).
Of course (as mentioned on another thread) some would say they are not really extinct, but are hiding out in Tasmania, but those reports have about the same credibility as Bigfoot sightings IMO.
It was taken at The National Zoo in Washington. Its a closeup/zoom of a larger photo which shows they are evidently in an enclosure designed for big cats- they are standing in the area adjacent to the indoor den.
Some of the older photos taken at the Hobart Zoo are also extremely sharp, including some of the more rarely seen ones. Look on the website 'Thylacine Museum' -it is very comprehensive.