Because Krautchan.net is an image hosting site - rather than a true chatroom - it would be very easy for someone then to upload that doctored image.

BBC: Was the 'gunman warning' a hoax?

Some news stories have multiple original sources, but in this case, no one has put their name either on the original, un-doctored image, or taken credit for the manipulation.

FORBES: Lion's Mane Jellyfish Image: This Is (Literally) How Things Blow Up On The Internet!

Just before the Express tour, a prominent Florida physician and tea-party activist named David McKalip forwarded a doctored image of Mr.Obama as a tribal witch doctor with a bone through his nose to a Google listserve associated with the movement.

WSJ: Birth of a Movement: Tea Party Rode Wave of Discontent

Some even use doctored photographs to advertise their qualifications: one image online shows a group of students said to be from the non-existent Wuhan University of Industry and Commerce standing in Tiananmen Square the original photograph shows the same group under a banner proclaiming who they really are: students from the Beijing Institute of Petrochemical Technology.

ECONOMIST: Fake degrees