DENVER (TheBlaze/AP) — A gay couple from New Jersey suing a group that used their engagement photo says they cringe when they see the image after it was used in an attack mailer against a Colorado Republican in a legislative primary.

Gay Couple Sues Over Photo in Anti Gay Political Ad | Public Advocate

Photo Credit: Kristina Hill Photography

The Southern Poverty Law Center filed a federal lawsuit Wednesday in Denver on behalf of the couple, Brian Edwards and Tom Privitere, and their photographer Kristina Hill against Virginia-based Public Advocate of the United States. NBC News has more about the photo’s origins and the resulting controversy:

…Privitere and…Edwards posed for their engagement photo, holding hands and kissing, in front of the Brooklyn Bridge in 2010. The image captured one of the happiest days of their lives. But earlier this year, their special moment was soured when the photo was used in two anti-gay mailers in Colorado.

On Wednesday, the couple and their photographer planned to file a lawsuit Wednesday in U.S. District Court in Colorado… They are seeking a court order saying the group violated the law, damages, costs and attorney fees for the allegedly unauthorized use of the copyrighted photo.

“We want to take back the beautiful moment in our lives that was reflected in our engagement photo before it was hijacked,” Edwards explained in an interview with NBC News earlier this week. “We also … want to take a stand for others who might be similarly targeted in the future.”

The photo was used in mailers in a June primary election against Sen. Jean White, who supported a civil union bill that was blocked in the state House. White lost the primary. As NBC notes, one of the mailers featured the image of the kiss and read, “State Senator Jean White’s Idea of ‘Family Values?’”

Gay Couple Sues Over Photo in Anti Gay Political Ad | Public Advocate

Photo Credit: Public Advocate

Another, which was aimed at House candidate Jeffrey Hare said, “Jeffrey Hare’s Vision for Weld County?” Hare lost his race as well.

It’s not currently clear how the photo made its way to Public Advocate to be used, although the couple did have an engagement blog where it was posted. Edwards, Privitere and Hill claim that they were never approached for permission to use the photograph.

“The use of Tom and Brian’s likenesses, or of Kristina’s copyrighted photo, was wholly gratuitous,” SPLC lawyer Christine Sun told NBC News. “Public Advocate could have just paid for a stock photo of a gay couple kissing but instead Public Advocate decided to take this very personal photo of this happy moment and use it to attack gay people.”