what i meant by that was you have to pay shutterstock for the licence. otherwise you must use the photo with shutterstock smeared all over it. per shutterstock:
Shutterstock content is royalty-free, but not free of charge (but we do offer a free photo and free vector each week, available on our homepage).
So while the images are royalty free, they are still owned and licensed by shutterstock. therefore NOT free unless you want to pay shutterstock for the use.