A new one! In http://bookgraphy.com/free-images you can download thousands of high quality free photos, available for personal and commercial use with model and property releases.
new site to download free photos http://absfreepic.com
Amazing photos. But i can't find any license on this site , it will be great if there is a CC0 mark.
There's some infos in the FAQ http://picjumbo.com/faq-and-terms/ but I guess you'll have to take their word for it :/
Just found this website after reading the other article. Great stuff.