It’s quite simple to find out if a Pin has been stolen. Simply hover your mouse cursor over a pin in your Pinterest feed. The website URL that the pin links to will show at the bottom of the pin. If you see one of your pins but it doesn’t link to your website URL, you’ve found a stolen pin.
If you click on a stolen pin, the website the pin now links to will open, not the website from where the pin originated.
Before repinning a Pin, always check that the Pin goes where it’s supposed to go so that you aren’t helping the thief.