We don't currently have that functionality in the module. You would need to do a template override for the file /mod_jfbcsocialshare/tmpl/default.php. Looking at the file, you should be able to easily add the SCPinterestShare easy-tag with code similar to below. However, you'll have to set the image to pin ($pinnedImage) and the description text ($pinnedText) to use for each page.
$pinnedImage = 'FULL IMAGE HREF HERE';
$pinnedText = 'YOUR TEXT HERE';
echo '{SCPinterestShare href=' . $href . " layout=" . $layout . ' image=' . $pinnedImage . ' desc=' . $pinnedText . $renderKeyString . '}';
I've added a feature request to our tracker to add this in a future release.
-Melissa
-Melissa