tiny green frog -- but what is it?

WE found this cute little frog on the Great North Walk -- near Piles Creek -- in a pond.
Does anyone know what sort it is -- it was about 5 cms from head to tail (but not including the legs).
My wife noticed you have a similar one on one of your banners -- is it the same?
Is it rare do you know?green frog
Thanks
Jonk