A photographer and a photo agency are teaming up to restart a legal war against online linking in the United States.

When Internet users browse websites containing images, those images often are retrieved from third-parties, rather than the author of the website. Sometimes, unbeknownst to the website author, the linked image infringes someone else’s copyright.

For more than a decade, courts have held that the linker isn’t responsible for that infringement unless they do something else to encourage it, beyond linking. Liability rests with the entity that hosts it in the first place—not someone who simply links to it, probably has no idea that it’s infringing, and isn’t ultimately in control of what content the server will provide when a browser contacts it.

Justin Goldman, backed by Getty Images, wants to change that. They’ve accused online publications, including Breitbart, Time, and the Boston Globe, of copyright infringement for publishing articles that link to a photo of NFL star Tom Brady. Goldman took the photo, someone else tweeted it, and the news organizations embedded a link to the tweet in their coverage. Goldman and Getty say those stories infringe Goldman’s copyright.

This claim is dangerous to online expression, and we've filed an amicus brief asking a federal district court to grant the defendants’ request to end the case as a matter of law.

For more than a decade courts have recognized that claims like Goldman’s and Getty’s are at odds with how the Internet works. When users visit a website, their computers send a request to that website’s address for a text file written in “Hyper-Text Markup Language” (HTML). That HTML text file includes, among other things, words to be displayed and web addresses of additional content such as images. HTML files are text only and don’t contain images—they refer to images according to their web address via in-line linking. The server at the linked web address may transmit an image in response to such a request, but the original website does not. The leading case is Perfect 10 v. Google, in which adult entertainment publisher Perfect 10 sued Google's Image Search service, arguing that Google should be held liable for any copyright infringement that occurred on sites to which Google linked.

The Ninth Circuit Court of Appeals correctly disagreed, ruling that because Google’s computers didn’t store the photographic images, the search engine company didn’t possess a copy of the images and therefore did not transmit or communicate them for the purposes of the Copyright Act. This approach is known as the “server test” because it looks to who actually houses the work on its server and controls whether it will “serve up” the infringing content. The rule established that the principal responsibility for any infringement lies with the entity that actually communicates the work to the world, rather than the myriad entities that simply tell browsers where to go to request access to an image file.

Linking is an essential tool for free expression and innovation. E-commerce sites can employ embedded links enabling consumers to comparison shop. Companies, schools, and libraries can use links to educate and empower users. Newspapers and bloggers use the Twitter posts of President Donald Trump in their stories. An art teacher can embed images of famous works on her web page for students to learn about particular art styles. These are all normal, everyday activities that Goldman and Getty would argue are infringement, tying websites into a legal knot and degrading users’ ability to learn and innovate.

We hope the court sees through this dangerous attempt to undermine the in-line linking system that benefits millions of Internet users every day.