Manychacha, I believe the original poster of this thread was looking for the "profile widget" which is what my work-around suggestion addresses.
But yeah if you just want a button linked to your Pinterest page to act as a follow button, that's as easy as uploading any image and linking it to your Pinterest profile, exactly as you did. Taking a screen cap of the image Pinterest generates on that page works.
If you don't require the image to be personalized like that, you could also use one of their logo images provided here: http://business.pinterest.com/logos-and-marketing-guidelines/. Or you can even just do a google search for "Pinterest social media button" or "Pinterest follow button", something like that, and there are oodles of options that can coordinate with buttons for other social media too if you want. See an example on my About page where I have matching buttons for Pinterest, Twitter, Email, and RSS.