You know all these personality tests cluttering up your Facebook? Which Classic Rock Band are You? Which Big Bang Theory Character are You? etc etc.
These things make pretty liberal use of iconic images, artwork and other images I'd assume would be subject to rigorous enforcement of copyright. For example, I imagine the Big Bang Theory logo is fiercely protected by the copyright holder.
So, are Buzzfeed, Zimbio et al just chancing their arm, or is there some fair use clause that means its cool to use other people's images, presuming you don't pass off or try to profit from them?