LibraryThing is offering free book covers that can be used for your webpage. They are offering these as a sort of thank you after members posted 1 million cover uploads. To use the covers you'll need to be a member, agree to terms and get a developer key. The covers come in 3 sizes and the details are outlined on the
LibraryThing Blog. The code looks simple to use and could offer a solution to legal use of coverart for your blogs or webpages. I haven't actually tried this yet but did sign up for a developer key.