From a close-up toothy croc encounter to bird attacking a ball of fish under the ocean, some of the best underwater pictures in the world have been revealed in this photography competition.

More than 4,000 pictures were entered for the Underwater Photography contest across 17 categories.

"Winning here, or even just being placed, is [our] most coveted accolade because it says you succeeded in the most competitive environment there is, against the top talent of the moment," said website owner and competition organizer Tal Mor.

"The panel of judges is comprised of industry professionals. They are unpaid, non-affiliated, and, of course, cannot enter themselves.

"Many other internationally acclaimed photographers have launched their photo careers here over the years … and we are so proud to be having a constant flow of new talent coming in. Our goal is – and always has been – to promote young talent and give them a stage to show off their photos and launch a career as underwater photographers.

"One of our medals is the reward for all the hard work they have put in chasing those great shots in far-flung destinations."

59-year-old Leena Roy scooped a gold medal in the "Wide-Angle Divers" category with her shot of a diver swimming through a cluster of silverfish in the Cayman Islands.