Google image search for the win! (Or TinEye:P)

The photo on arkive had the photographers name, Thomas Marent and a link to ardea.com. His images are here:

www.ardea.com - wildlife, pets, environment

On the right, hit "Search Within" and search for Hyloscirtus lindae to see a few more of this specific frog. Search for just 'frog' to see many other terrific photos. The non frog stuff is great too.

edit- He also has a gallery on his webpage for frogs Thomas Marent Wildlife Photography |*AMPHIBIANS but be warned it auto plays an annoying rainforest sound Why oh why?