The Washington Post has a policy about photo manipulation like many other newspapers across the country. Summary of the points include: nothing is added or subtracted from the image such as a hand or tree limb in an inopportune position, silhouettes should be used sparingly, photos in collage artwork is permitted for illustrative purposes only, and take a reality check.
These are relevant points because the photographer deserves the credit for the image, and also that is their artform. C.J. discussed in class very briefly that a small change in a photo can make someone seem married or just engaged. That is another reason that a photo shouldn't be changed.