Pinterest Button Reveals Hidden Demo Images

I just downloaded a Pinterest button in my Google chrome browser. When I visit my website and click this button, a list of pictures come up with the option to pin them in Pinterest. I was surprised to find that some of the images that came up were not images that I could see on my site. They were the sample images that come with the Highend demo content, specifically the images from the sample portfolio items. I went to my portfolio items and made them all private. This didn’t change anything in regard to the Pinterest button issue. How are these images showing up in the Pinterest app when I can’t see them on my site? And how can I remove them without deleting the demo portfolio items?