I repeated the same experiment with different results. Searching "World Trade Center" in either personal or general results show no thumbnail links to the image search. There was one thumbnail linking to the news search, but it was a memorial picture. Searching "Oklahoma City" did list the image search thumbnails. The thumbnails were followed after six entries, if you include the Google Maps link. Only one of the four was related to the bombing, and that one picture was a distance shot of the build, not of human remains.