Student Chris Brown had found the images from the club's website while it was being updated. He did not hack the site, BBC News reports.
He was phoned by the club at 4.30am yesterday (Wednesday) after posting the images on internet forums and Twitter the night before.
Norwich chief executive David McNally said: "We are the guardians of the football club while we're here and so we will protect our property.
"And our property in the digital age involves our intellectual property, so we won't allow anybody to come in and take it from us."
Season ticket holder Brown said: "I'm sorry for any offence I might have caused to the club, but I would never do anything malicious or spiteful because I do have an interest and love the football club."
In a statement, Norfolk Police said: "We can confirm we are making inquiries into a reported electronic security breach. A 17-year-old boy is assisting us with our inquiries."
> Footballers play rock, paper, scissors over free-kick - video
> Lingerie Football League set up in Australia, heading to Europe