Samantha Busch, a 22-year-old from Illinois, asked her boyfriend to take the shot, which suggests she is about to tumble from a cliff-edge into the chasm below.
Despite the expression on her face, she was in fact standing on a ledge out of sight below. She added the image to Reddit, the social networking site, with the caption “Mom was worried about my trip to the Grand Canyon, I sent her this picture".
Since its posting, the photograph has received thousands of comments, and has even attracted other copycat images.
Ms Busch said she sent the picture to teach her over-anxious mother a lesson.
[Related: Things to do in the Grand Canyon]
“For five days up before I went on this trip, she [her mother] was worried about us visiting the Grand Canyon, because 'people are dumb, they fall off, the wind blows over them the edge',” Busch explained to ABC News.
“So when while I was there, I found a cool little spot that I could sneak into, and lean back and look like I am falling off, and I thought that would be a great picture to send back home to my parents, who were worried about me.”
Her act apparently had the desired effect. “My heart just dropped for 30 seconds,” her mother, Rebecca Busch, said. She did later say she had forgiven her daughter.
Read more on The Telegraph.