The former party leader took the mistake in good humour. He deleted the picture from Instagram and posted on Twitter "The wife is chortling about the willy picture. She says in future she'll be be the one checking the pictures I put on Instagram."
Ohly also wrote that former leader of the Social Democrats Håkan Juholt wrote him a text message: "Was going to barbecue sausages tonight. But now I think it'll be chicken instead."
And one of Ohly's political opponents, foreign minister Carl Bildt of the centre-right Moderate Party wrote: "Congratulations on finally achieving a genuine breakthrough". Ohly was not shy about re-Tweeting the jibe.
"What a lot of new followers I have on Instagram today," he wrote. "And how disappointed they're going to be."
Lars Ohly is a member of the Swedish parliament, and was leader of the Left Party between 2004 and 2012. In the last election it got 5.6 per cent of the national vote, and has 19 members elected to parliament.