A few nice animals for free images I found:
Amur Leopard (Panthera pardus), Colchester Zoo
Image by spencer77
Used for an article about endangered animals www.halabol.com/top-10-animals-verge-extinction
This picture is available to use for free, under the creative commons licence. All I ask is that I'm given a photo credit & a courtesy email to let me know how it's being used.