Sometimes the images link to free patterns, sometimes to patterns you can buy, and sometimes just to a photo. And, as you've discovered, sometimes to a black hole! It's a place to 'pin' ideas. You may not have a pattern from an image, but you will be able to keep the idea. If you are able to knock off your own patterns or draft from a picture, no problem. But if you need an actual pattern, you won't always find one.
I love Pinterest and have thousands of things pinned. It has replaced "bookmarking" for me.