I was flipping through Facebook the other day when I saw a nice photograph. I thought I would like it on my Pinterest board but you cannot pin photos from Facebook to Pinterest. Then a little later I saw another nice photo but below it this time was a link saying Repin: and giving the URL. When I clicked the URL, it took me straight to that picture on Pinterest. So I experimented tonight. I picked a photo from my Pinterest account that is from one of my websites, and copied the URL. I then pasted that URL into my Facebook account and it brings up that exact photo. I then typed in Repin and the URL and I now have a copy of the photo AND the Pinterest URL on my Facebook account, for people to click through if they want.
Just FYI, if you want to spread the net further.
I have tried this a couple of times. Sometimes the picture shows, sometimes it doesn't but the link is live.