"It's the logo for Google's AdChoices system. Facebook will start using the system on most of its site ads very soon. If you see the logo on an ad, it means that you are seeing personalized ads based on your past browsing history.... instead of picking up bits and pieces from your browsing, AdChoices might just pull your Likes, groups and other information directly." Read the article for how to turn it off.
If you want to pin a picture directly from Facebook.. 1. Install the "Pin it"-Bookmarklet 2. Click on the Facebook picture you want to pin 3. Right-click and choose "view image" 4. Make sure the .jpg-URL is shown in your in your browsers address bar. 5. Pin it