A federal judge said yesterday that an adult-entertainment company is likely to prevail in at least one aspect of a copyright-infringement suit against Google, and he ordered the companies to work out the wording of a possible preliminary injunction.

The suit focuses on Google's Image Search feature.

Perfect 10, which produces an adult print magazine and website, alleges Google has violated its copyrights by, among other things, showing thumbnails of images from Perfect 10's collection and providing access to larger images on third-party sites that also infringe the copyrights. It sued Google in November 2004 and is seeking a preliminary injunction to stop Google from displaying the images.

In an order issued yesterday, Judge A Howard Matz of the US District Court for the Central District of California delivered a mixed decision: he granted parts of Perfect 10's motion for a preliminary injunction and denied other parts. Matz ordered the two companies to jointly present, by 8 March, the proposed wording of a injunction that balances intellectual property rights with the importance of access to information.

It is likely that Google infringes on Perfect 10's copyrights by creating and displaying thumbnail images in its search results, Matz wrote in the 47-page order. He cited Perfect 10's partnership with Fonestarz Media, a UK company, for worldwide sale and distribution of reduced-sized copyright images for display on mobile phones. It's likely that the thumbnails Google provides harm the potential market for those images, he wrote.

However, among other things, Perfect 10 would probably fail in its argument that Google "displays" infringing images that reside on third-party sites, Matz wrote. Users can see those sites underneath a Google "frame" after they click on a thumbnail on the search results page.

The intellectual property rights issues in the case have to be balanced against the value to the public of search engines, which are "essential sources of vital information for individuals, governments, non-profits, and businesses who seek to locate information", Matz wrote.

Google expects to appeal any injunction, according to an emailed statement attributed to Michael Kwun, Google litigation counsel.

"We anticipate that any preliminary injunction will have no effect on the vast majority of image searches, and will affect only searches related to Perfect 10," the statement said.

An attorney for Perfect 10 did not return a call seeking comment.

Perfect 10 has also sued Amazon.com and its A9.com unit for copyright infringement and moved for an injunction against them. The Amazon and Google cases have been consolidated, but Perfect 10's motion against Amazon will be addressed in a separate order.