The incident is the latest in a global wave of high-profile hacking attacks.
Woori Bank reported a hacking attack, but said it had suffered no damage.
However, during a hacking attack on the board where the images were posted, most of the images were lost.
The incidents are the latest in a series of high-profile hacking attacks.
In July 2012 the website was reportedly subject to "massive hacking attacks over a week."
And cables show repeated, often successful hacking attacks on the United States government.
Cloak & Dagger then became an internet podcast, which subsequently relocated to a German web server due to relentless hacking attacks.
On September 11, 2004, the site was subjected to a major hacking attack, during which the site's databases were accessed and several weeks of diary entries were erased.
The Open Diary website has been the victim of two major hacking attacks.
He was also charged with a hacking attack on the U.S. security company Stratfor in December 2011.