Don’t assume that online site will “always be there” and you can always go and get what you need. Make a copy of that image for yourself while you have it on your screen. Save the information while you have access to it.
Websites go down. Fee-based websites sometimes lose the ability to include certain items in their subscription. Websites change how things are organized and what you could find a month ago is impossible to find. Your cousin could remove their online tree from that hosting site.
You may find yourself unable to continue to pay for that monthly subscription to that database site that includes images.
Save it while you can. Name it in a way that makes sense. Save it where you can find it. Make backup copies.
Later you will be glad you did.