Here's some links for you:

https://torrentfreak.com/embedding-copyright-infringement-eu-court-rules-141025/

https://www.techdirt.com/articles/20100105/0109067611.shtml

http://www.dvorak.org/blog/2007/12/19/is-hotlinking-stealing-does-it-infringe-copyrights/


Anyways, if it did violate the dmca amazon would need to send them a notice, and if it doesn't violate their terms they're unlikely to do so (plus they wouldn't care unless it's a lot bigger than it is now).