Watermarked image

I’m using watermark plugin that is using htaccess to watermark images on my site;
The plugin url: https://wordpress.org/plugins/wp-content-copy-protector/
When I share my products in tumblr, tumblr fetch images url from my site and images have watermark and works properly;
BUT when I share my products in Pinterest, Pinterest fetch images from my server directly and images don’t have watermark.
I hope to consider this problem and fix this issue.