Either he owned the site and put up the pics himself with his own manifesto, or the website was fake, the manifesto was fake and the pic was fake. The only other option would be if he photoshopped the picture himself. Pretty sure your head would explode if that was the case though. PS whatever that site was is complete horseshit. Wait, let me go make some purple dots on an image and call it 'forensics'.Over the weekend, a website registered in Roof's name came to light. It featured several photos of him along with a written manifesto. Authorities are still determining the authenticity of the site.
http://www.bbc.com/news/world-us-canada-33228707
EDIT:
I traced back one of the photos to this twitter, which has him in the same shirt and in similar poses. This most likely won't end well for you..
https://twitter.com/lolnoor/status/612433294580416513