[cmiles74]

Pinterest is caching these images on their servers, not their customers who are only pasting in links. I find it hard to believe that these end-users will be held liable for an implementation detail on Pinterest's end. And linking, I believe is legal.

These are images that are publicly available on the internet and have been made available, in most cases, by the owner. Is there really a case that copying these images off the internet is illegal?

[ceol]

It's not an issue of copying images off the Internet. It's an issue with redistributing it, which Pinterest does. Just because an image is on the Internet does not mean it's up for grabs to whoever gets it.