A record 60,466 nature people voted, and German photographer Sascha Fonseca's "World of the snow leopard" emerged as the firm favorite in the prestigious competition.
Fonseca used a camera trap to capture the image of the rarely sighted big cat at sunset, with a backdrop of mountains in Ladakh, northern India.
The image was selected from a shortlist of 25 that were chosen by London's Natural History Museum from nearly 39,000 entries.
There are estimated to be just 6,500 adult snow leopards living in the wild today, and their existence is threatened by poaching, habitat loss and conflict with humans.
Thanking everyone who voted for his picture, Fonseca said in a statement issued by the museum: "Photography can connect people to wildlife and encourage them to appreciate the beauty of the unseen natural world. I believe that a greater understanding of wildlife leads to deeper caring which hopefully results in active support and greater public interest for conservation."
Natural History Museum director Douglas Gurr said in the statement: "A result of dedication and perseverance, Sascha's remarkable image captures the breathtaking beauty of our planet and reminds us of our shared responsibility to protect it."
One of the four images selected as "highly commended" also features a leopard, though not of the snow variety. In "Holding on," Igor Altuna captured a leopard carrying a dead monkey and its baby.
Brittany Crossman's "Fox affection" shows red foxes nuzzling, while a polar bear cub plays on the coast of Hudson Bay, Canada, in Martin Gregus' "Among the flowers." Lastly, Marina Cano's "Portrait of Olobor" depicts a majestic male lion in Kenya's Maasai Mara.
The Natural History Museum said in its statement that the exhibition harnesses photography's "unique emotive power" to "shine a light on stories and species around the world" and help create advocates for the planet.
Call to Earth is a CNN editorial series committed to reporting on the environmental challenges facing our planet, together with the solutions. Rolex's Perpetual Planet initiative has partnered with CNN to drive awareness and education around key sustainability issues and to inspire positive action.