* They provide a Pin It button under the posts. Not on top of the images. Adding one more social media sharing button underneath the post adds no advantage. And most people don't even look at the sharing options anymore.
* Some of the solutions out there are paid. I found one that asked for $17 for a Pinterest plugin! (I have no idea why someone would pay for a social media integration plugin...)
So I quickly created a WordPress Pinterest Plugin that shows a Pin It button on your images - only when people move their mouse over it.
Its available for free:
WordPress › Pinterest Plugin « WordPress Plugins