(CNN) Josh Rossi photographs superheroes. In one session, he got Superman to stand still long enough for his red cape to artfully billow. This "man of steel" -- actually a determined nine-year-old with a life-threatening heart defect -- is indeed more powerful than a locomotive.

As part of an unusual photo project, Rossi and his wife Roxana transformed six children with major illnesses and disabilities into members of the famed Justice League. The images attracted more than 100 million online views.

Rossi started his Justice League project after a Halloween photo shoot with his daughter, Nellee. He created digitally-enhanced backgrounds, dressed the healthy, spirited girl as Wonder Woman and had her strike a pose.

The photos struck a chord with parents of critically-ill children around the world.

"I had people contact me saying, 'This is my child — they are the real superheroes.'"

Five-year-old Simon Fuller, diagnosed with neuroblastoma, was featured as the Justice League's Batman.

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