The site http://periodictable.com/ has a lot of great images. Allmost all images excluding a few have 'Copyright © Theodore W. Gray' watermark on them. So the ones which don't have this watermark, Are they free?
closed as off-topic by heavyd, Journeyman Geek♦, Carl B, BBlake, Mike Fitzpatrick Dec 19 '13 at 21:56
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