Here are two examples of fake UA175
photographs I quickly made in Photoshop using Flight Simulator to generate the
correct image of a Boeing 767. It took about 1 hour to manufacture each image
and they aren't particularly convincing, but it does demonstrate that
photographic forgery is achievable for the layman.
Please note the second image is deliberately showing a Boeing 767-300 unlike
the Boeing 767-200 below:
If this is what can be achieved by a
novice Photoshop user in an evening then imagine what a skilled team of
professional forgers could achieve in a few days.