I believe this is still contested in some respects, but there has already been one case which decide it was not copyright infringement: http://en.wikipedia.org

I believe this is still contested in some respects, but there has already been one case which decide it was not copyright infringement: http://en.wikipedia.org/wiki/Perfect_10,_Inc._v._Amazon.com,_Inc http://en.wikipedia.org/wiki/Perfect_10,_Inc._v._Amazon.com,.... "The court held that Google's framing and hyperlinking as part of an image search engine constituted a fair use of Perfect 10's images because the use was highly transformative"