Remove PinIt button on specific images

Hi Warfare Team,
I really love your product and I am really happy to use it on my site. I am writing on the forum instead from your site because I think that this question can help other users.

I remember that was possible to deactivate the PinIt button on certain images by adding a simple CSS class, the problem is that I do not remember anymore which class it was…

I’ve tried with nopin but it does not work, can you help me up with this?

Thank you in advance,
Andrea