Images with captions break the rest of the content when using the plugin. captions are placed between [caption][/caption] short code with the <img> tag between the caption tags.
also have a peek at this previous post. http://wordpress.org/support/topic/plugin-pinterest-pin-it-button-for-images-suggested-improvements?replies=4
http://wordpress.org/extend/plugins/pinterest-pin-it-button-for-images/
