In December, documentary photographer Carol Highsmith received a letter from Getty Images accusing her of copyright infringement for featuring one of her own photographs on her own website. It demanded payment of $120. This was how Highsmith came to learn that stock photo agencies Getty and Alamy had been sending similar threat letters and charging fees to users of her images, which she had donated to the Library of Congress for use by the general public at no charge.

Now, Highsmith has filed a $1 billion copyright infringement suit against both Alamy and Getty for “gross misuse” of 18,755 of her photographs. “The defendants [Getty Images] have apparently misappropriated Ms. Highsmith’s generous gift to the American people,” the complaint reads. “[They] are not only unlawfully charging licensing fees … but are falsely and fraudulently holding themselves out as the exclusive copyright owner.” According to the lawsuit, Getty and Alamy, on their websites, have been selling licenses for thousands of Highsmith’s photographs, many without her name attached to them and stamped with “false watermarks.”

Since 1988, Highsmith has been donating tens of thousands of photographs of people and places in the United States to the Library of Congress, making them free for public use. The institution calls the donation “one of the greatest acts of generosity in the history of the Library.” The Carol M. Highsmith Collection is featured in the library’s Prints & Photographs Division, alongside the likes of Dorothea Lange’s Dust Bowl and Depression photographs.

In fact, it was partly Lange’s work with the Farm Security Administration that inspired the now-70-year-old Highsmith to begin her own project of documenting all 50 states through her nonprofit This is America! Foundation. Chances are, you’ve seen the results before. The United States Postal Service featured Highsmith’s photographs of the Jefferson Memorial and the Lincoln Memorial on stamps, and her work has appeared in Smithsonian Magazine, Time, the New York Times, and the Washington Post Magazine.

Since each violation of copyright in this case allows the plaintiff to seek damages up to $25,000, the statutory damages for Getty’s 18,755 violations amount to $468,875,000. But because the company was found to have violated the same copyright law within the past three years — in 2013, Daniel Morel was awarded $1.2 million in a suit against Getty, after the agency pulled his photos from Twitter and distributed them without permission to several major publications — Highsmith can elect to seek three times that amount: hence the $1 billion suit.

“The economic damage that Ms. Highsmith has suffered includes, without limitation, any and all revenue received by the Defendants based on purported licenses sold for the Highsmith Photos. These funds represent money that Ms. Highsmith could have received had she attempted to monetize her photos through the Defendants,” the complaint states.

“The injury to Ms. Highsmith’s reputation has been … severe,” it continues. “There is at least one example of a recipient of a threatening letter for use of a Highsmith Photo researching the issue and determining that Ms. Highsmith had made her photos freely available and free to use through the Library website. … Therefore, anyone who sees the Highsmith Photos and knows or learns of her gift to the Library could easily believe her to be a hypocrite.”

Update, 8/1, 2:40pm: Getty Images has issued a statement that says the company is reviewing Highsmith’s complaint. It also states: