Here's a detail of the train station one at 100% zoom.
I think the artifacts are pretty obvious.
I'm not sure on the NYC one. The whole thing looks a little blobby - as if there was some aggressive noise reduction, but nothing bad enough to point out any specific areas. There are some strange light streaks in the sky that seem to be emanating from the clouds on the right side - almost like a radial blur snuck in there for no reason. That might have been it.