well, now we have to question the motives of those who are looking for photos of the before skyline; item:

LOS ANGELES, California (Reuters) -- The online auction site eBay has banned the sale of all World Trade Center and Pentagon memorabilia after everything from chunks of rubble and bits of glass to video tapes of the disaster appeared for sale within hours of Tuesday's attacks.
...
The ban covers legitimate items such as postcards of the soaring twin towers of the World Trade Center -- a landmark now obliterated from the New York skyline -- as well as more grisly mementos seized by bounty hunters from the rubble.


I heard a report on CNN that someone was attempting to sell "before" postcards for $30 per.