Personally i don't give a damn about taking images from google and using them. I certainly don't quote the source on my own sites. Nobody ever griefs me up, and on 2k+ hubs, I've only ever had 2 messages. One asked me for a link, and the second loved that i had used their photo in my article.
The worst that will happen is they complain with a dmca, but nobody really does that with pics, since we are all 'borrowing' each others photos anyway. Use the google method, wait till they contact you first.