In the frame of a Apollo missions being an hoax, an argument is that there are reasons to believe that photos shown can not have been taken on the Moon.
By analysing the photo taken by NASA in detail, a professional photographer came to the conclusion that there are obvious reasons that these photos are been taken in a studio. Sources indicate that film director Stanley Kubrick might have hired by NASA for doing this since his previous experience with the SD movie "2001 Space Odyssey" 
Professional photographers who examined the photo were not expert on space photos. The analysis was not conducted on the original photo, but a copy that has been already modified. Digital photography was not available in the 70s; therefore photo manipulation techniques were much less sophisticated.
Among the anomalies present in the photos some are: 1) The American flag can not blow on an airless Moon? 2) No stars are appearing in back-ground?
Rejecting the premises
The counter-arguments to this objection are: 1) The flag had a special horizontal rod to keep it standing; oscillations were due to some inertia, 2) The stars are not showing due to high luminosity of Moon surface