If you have the Pinterest plug-in enabled in your browser as I do, when you hover over the image below a bright red Pinterest “Save” button will display in the top-left hand corner.

As a web developer/designer, you may not want this bright red button ruining your “aesthetic”. If you want to turn off Pinning on a single image, add this tag to it:

<img src="foo.jpg" nopin="nopin" />

You can also use the following meta tag in the header of your pages:

<meta name="pinterest" content="nopin" description="Sorry, you can't Pin from my website!" />

Source: https://help.pinterest.com/en/articles/prevent-pinning-your-site