If you steal images for teasers and music for their trailers, that is also piracy. You're profiting off another's work!
And now, the bloggers who are helping authors by promoting their stuff on their page via blog tours and such are getting in trouble for hosting these illegal images.
I can understand using a pic of a celebrity and saying he/she is the kind of what the character looks like, but it seems like they are using the images of celebrities to market their book.
As for pictures, I will use some models for FUN among those in my GROUP. Never for actual promotion.