A family whose image was used in a poster campaign by a group opposing gay marriage in the Irish Republic say they were "naive" about stock photo sites.
The photo had been placed on a website by a photographer in return for a free photo shoot, with the family's consent.
They told the BBC that while the Mothers and Fathers Matter group had legitimately used their image, they did not agree with its message.
Ireland voted in favour of same-sex marriage in its referendum on Saturday.
Around 62% of voters were revealed to be in favour of legalising it with 38% against.
The British couple featured on the posters, who asked not to be named because of the sensitive nature of the gay marriage debate, said the pictures were taken in 2014.
They were given free copies in return for allowing the photographer to sell them on stock image websites but said they assumed if they were ever used at all, it would be "for a small magazine or website".
"The chances of having your photo selected out of all the hundreds of thousands available are pretty slim," the father in the poster told the BBC.
"The photo was not stolen from us... we have no claim over (or rights to) the picture, and we do not claim otherwise," he added.
"We just wanted publicly to say that we disagreed with the No campaign and were unhappy about their use of our image, but we acknowledge that they're allowed to do so."
He added that he was surprised the campaigners had not chosen images of people they knew were supporters.
The BBC has contacted Mothers and Fathers Matter for comment.
A spokesperson told the Irish Independent that the group had not heard from the family but would be happy to discuss its views with them.
The couple told the BBC they have not pursued this offer.
They said their pictures have also been legitimately used by an Irish fertility company and an Australian legal firm, and added that they have no regrets.
"We got some lovely pictures and we agreed to let the photos to be added to stock. We were just unlucky this time," the father said.
In a statement released via Human Rights campaign group Amnesty International in Ireland the pair laid out their own views on the gay marriage debate, although as non-Irish citizens they were not involved in the vote.
"This family believes that everyone has a right to marry the person they love regardless of their gender," they said.
"And this family would vote Yes [in favour of legalising same sex marriage]."