Pickerel frog

Thanks for confirmation, folks, but...
Can anybody tell me the difference between Pickerel and Leopard???

Easy one, I first sought... Then I stumbled over Pickerel and Leopard frog and now I am no more so sure ;-)...
In my eyes it looks like being the Pickerel Frog, Lithobates palustris. But I might be wrong... Please, verify and check some links and pictures I found, I would not dare to make a suggestion...
http://www.virginiaherpetologicalsociety...
http://www.virginiaherpetologicalsociety...
http://www.virginiaherpetologicalsociety...
https://en.wikipedia.org/wiki/Northern_l...
http://www.frogforum.net/content/leopard...
http://www.virginiaherpetologicalsociety...
http://www.virginiaherpetologicalsociety...