I think Adobe is fine with it, Pinterest might have a problem.
For a while I tried to put a link to a stock site onto my pictures that other people had posted on Pinterest without my permission. I never could get it to stick. If you read the TOC on Pinterest you are basically saying that you own the rights to the image you are posting and that you are giving it to Pinterest to give away to anyone - or that is what it appeared when I looked at it a while ago. Obviously most of the pins are not of images that the pinners own the rights to, but as long as nobody sues they are fine with that - if someone does sue I am sure they will pass the liability buck along to the poster.