Well this has been debated often and in my view this is covered under fair use.. And I  think that Kort had good intent by trying to find the original creator of the artwork.. The law is very tricky regarding this topic, and you are more liable to be safe if the artwork is on long term display, rather than temporary, and it always pays to be able to give the credit of the artist.... I  hope the copyright laws dont get us into the situation where we cant take say an image of a building as it has a corperate logo on view!!

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt