After joining Pinterest, the very first thing you should do is install the Pinmarklet (“Pin It” button).  This is a little button you add to your toolbar, to let you Pin from (pretty much) any page on the internet.  This way, even if the page doesn’t specifically have a “Pin It” button, you can still save whatever you want to your boards.

(Just use common sense and common courtesy.  If an image is an artist’s primary work, there’s a good chance he doesn’t want it spread all over the internet.  Likewise, be very careful Pinning pictures that have people’s children.  Ask yourself, “If this were my picture, would I be comfortable with it being Pinned to Pinterest?” If the answer is yes, you’re probably okay to go ahead and Pin it.  And, by the way, apart from photos of children, which some people are not comfortable having spread around, most bloggers love it when you Pin their posts, because that means more people will see them.)