If you follow the links on the Pinterest photos you want to use, and find that they have Creative Commons licenses, then you could certainly use them. Otherwise, I don't think this is a good idea, unless there is a link to the photographer -- not so that you can simply put the link in your hub next to the photo, but so that you can contact the photographer and ask them for permission to use their work in your hub. Linking and/or attributing is not enough; you need permission. Think of it in terms of your writing -- you'd be mad if someone copy/pasted your work onto their blog or website without your knowledge and permission. Same with photos.
There are all millions of average, everyday people on Pinterest, and my guess is many of them, if not most, do not have any clue that they cannot post photos which are not theirs willy-nilly as they please. Just because someone has used a photo on Pinterest doesn't mean they used it legally. I would imagine Pinterest is filled with illegally used images.
I have gotten to the point that I only use my own images, or I find one on Wikimedia Commons or Flickr Creative Commons or some other site where I can sort photos by license, and choose only photos with a Creative Commons license.