Actually in traditional medieval folklore dragons were generally four-limbed like this. Something I didn't even know until recently. Wyverns were differentiated by being smaller, with a barbed tail, venomous bite, and inability to breathe fire. Dragons were much larger (far bigger than the guy in this picture), generally had an arrowhead-tipped tail, and breathed fire. Six-limbed dragons actually weren't standard dragon fare until Tolkien created Smaug in the 40's.
This picture is a wyvern by the traditional definition in appearance. Number of eyes and shape of the jaw weren't specified. Just trying to help you learn something new.