Google may have to modify its image search technology after a pornography company won an injunction against the search giant for breach of copyright.

Perfect 10, which produces a magazine and website featuring "natural women", is claiming that Google's image search feature infringes its copyright.

The firm also alleges that the search engine is linking to sites where pirated copies of its images are stored.

Perfect 10 originally filed a separate suit against Amazon, but has now combined both actions into a single case.

"The court now concludes that Google's creation and public display of 'thumbnails' likely do infringe Perfect 10's copyrights," wrote US District Judge A Howard Matz in a 48 page ruling. 

"The Court also concludes, however, that Perfect 10 is not likely to succeed on its vicarious and contributory liabilities."

Judge Matz explained that Google derives no financial benefit from the images and that it is the company hosting the pirated images which is at fault, making a damages claim against Google unlikely to succeed.

Google is not contesting that the thumbnails are copyrighted but does dispute the assertion that it is infringing those rights. The search giant insists that its display of the images constitutes 'fair use'.

The two parties were directed to collaborate on a joint injunction that will protect Perfect 10's copyright, but not curtail Google's ability to categorise the web. The sides must reach agreement by 8 March.