Sure the photos were staged, as most science photos are. They represent an oversimplification. But, from your link,
Its validity rests upon experiments conducted by researcher H.B.D. Kettlewell during the 1950s, which demonstrated that white moths do have an advantage over dark moths on pale trees, and a disadvantage on dark trees, and vice versa.
While his results were criticized, there is no indication they were faked, nor that they were completely wrong.
If there weren't many black moths around at the time the photo was taken, they have had to use a specimen. The photos are illustration, not evidence.