Celebrity blogger Perez Hilton, who runs what he calls "Hollywood's Most-Hated Website," has been hit with a $7.6 million US lawsuit by a photography agency.

X17 Inc., a Los Angeles-based agency that photographs stars in personal or embarrassing moments, has filed a federal copyright infringement lawsuit against the internet gossip hound.

'We've had trouble with a lot of bloggers but he's the biggest, and most arrogant, and pigheaded.'-Brandy Navarre, co-owner of X17

"He is stealing our images and costing us money every day," X17 co-owner Brandy Navarre told the Los Angeles Times. 

"We've had trouble with a lot of bloggers but he's the biggest, and the most arrogant and pigheaded."

The suit alleges Hilton, born Mario Lavandeira, used 51 photographs without permission, credit or payment. Those include images of a pregnant Katie Holmes and Britney Spears unveiling her panty-less condition as she got out of a car.

The two-year-old site, which is updated up to 12 times a day, posts photos with sassy captions and cheeky bits of rumour and gossip.

PerezHilton.com has become a destination for gossipmongers. The self-styled "gossip gangsta'" has become a star in his own right, attending parties and events. He is expected to earn six figures this year.

Hilton said he would fight the suit.

"I am willing to step up to the plate and fight for my rights and fight for the rights of all bloggers."

Hilton has also argued the lawsuit is aimed at destroying his popular site for the benefit of X17online.com, which started in June.

His lawyer, Bryan Freedman, warned that the suit threatens freedom of expression, specifically the right to make satirical or humorous use of photos.

John Tehranian, a lawyer for X17, contends Hilton is "free-riding on the labour and efforts of X17 and its photographers."

X17 can make tens of thousands of dollars from one magazine on an exclusive photograph.

Seven other photo agencies have sent a joint letter to Hilton demanding he stop using their photographs. They have not sued.