According to Åkesson's press secretary Henrik Vinge, the pictures were taken at a private summer party at Åkesson's house this past weekend. They have been spreading on social media because of the controversy surrounding Ultima Thule, who have been linked to nationalistic extreme right-wing movements.
"The Sweden Democrats have so much wind in their sails that they no longer have a problem showing who they really are," Daniel Poohl, director of the organization EXPO, told news agency TT.
Henrik Vinge is not surprised by the furor the picture has caused.
"I thought it would be a bigger deal. Many think that Ultima Thule is controversial, which can be good to create a discussion, because it is largely a misunderstanding," Vinge told TT.
Ultima Thule released their first single 30 years ago, and it was sponsored by the racist organization Keep Sweden Swedish.
"This shows the Sweden Democrats' political affiliations. It is a party that comes from nationalist and right-wing extremist miljieu, where Ultima Thule is matter of course," Poohl said.
According to Vinge, the band has distanced itself from racism. But like Poohl, he describes them as a force in the nationalist movement.
"During a time when it was considered ugly and controversial to be nationalistic and to protect the common culture and the Swedish heritage, Ultima Thule has been a symbol of opposition, and something people could gather around," Vinge said.
More recently, the Sweden Democrats have tried to portray themselves as a more socially conservative than nationalistic party. That the party leader is now posing with the nationalist band is a step away from that line, according to Poohl.
"Many of the new voters have not voted for a party that you see hanging out with Ultima Thule, rather as a party that has been understood to have been housebroken. And Ultima Thule is not housebroken," Poohl said.