Nat Geo has a feature they call "Your Shot," where readers can submit interesting photographs for publication. In the February issue they printed a photograph of a close up picture of a dog with his attention fixed on the photographer, and six Blue Angels jets streaking through the background.
In the June issue just out, they report that several readers questioned the authenticity of the picture. After some investigation the magazine decided it was a composite; the rules specify "unmodified camera images."
The picture shows the dog in sharp focus, with a tree and house in the background somewhat out of focus as if a large aperture had been used. Then the jets, which are obviously farther away than the house or tree, appear to be in fairly sharp focus. The article revealing the fake says that the editor who reviews these submissions looks at 300 pictures a day. She's going to be working a lot of overtime to catch the faked photographs possible in today's digital world.