Step 1: In Pinterest, click on the button in the top right hand corner that allows you to add a pin. Choose upload a pin.
Step 2: Choose the image from your computer you want to pin. (Etiquette is that you only pin your own images, not those from someone else's Facebook page. - If you really want their picture pinned, share this page with them!)
Step 3: Select the Pin Board you want to pin to and also write a catchy description and Pin it.
Step 4: Hop over to your Facebook page and in your photo album, click on the picture you want to pin and it will bring up a screen with the picture, your description and any comments made. Copy the URL.
Step 5: Find the pin you just created. Click the little pencil to edit your pin. Here you can change the Pin Board, description AND you can add a source for the pin. Paste the URL into the source field. Save changes.
Here's a link to the Pin created in this blog post: