The photo was taken outside the window of a constituency office in Durham in the days leading up to the Hartlepool by-election last year.
At that time, the restrictions allowed people to gather indoors for work purposes but not for social gatherings.
The timing of the re-emergence of the photo comes as pressure on Boris Johnson to resign intensifies following reports of another party in Number 10 being held while the country was under COVID restrictions.
On Thursday it was reported two more parties - including a leaving-do for the prime minister's former head of communications - were held on the day before the Queen buried Prince Phillip and was forced to sit alone in a church on 17 April.
Amid growing public fury and calls for the prime minister to resign, the Telegraph reported on Thursday night senior Conservative sources branding Starmer a "complete hypocrite" over the photograph.
“Sir Keir has spent the past two months criticising people for doing the exact same thing he's been doing himself,” they said. “He is an absolute hypocrite.”
Labour has dismissed the re-emergence of the photo, which was first reported last summer, suggesting it was an attempt to distract from the pressure facing the prime minister.
Emily Thornberry, shadow attorney general for England and Wales, insisted no rules were broken.
"When it came out eight months ago, we didn't cover it up - we explained straight away because there's no problem with it at all," she told TALKRadio.
She added: "He had a Zoom meeting with a large number of people and the event went on and he had something to eat, and a bottle of beer, and someone took his photograph through the window.
"That's it and, frankly, is that an equivalent to going into a party in the Downing Street garden?"
When approached by Yahoo News UK, Labour pointed to a statement they made when the story emerged last year.
"Keir was in the workplace, meeting a local MP in her constituency office and participating in an online Labour Party event," a spokesperson said.
"They paused for dinner as the meeting was during the evening. No rules were broken."
Watch: Emily Thornberry defends Sir Keir Starmer beer picture
Downing Street has apologised to Buckingham Palace for the gatherings held the day before the Duke of Edinburgh’s funeral.
Two events reportedly took place at Downing Street, with the Prime Minister’s former director of communications James Slack apologising for the “anger and hurt” one of the events – a leaving-do held for him – had caused.
A spokesman for the Prime Minister confirmed No 10 has said sorry to the Palace.
The day after the events on April 16 2021, the Queen attended her husband Philip’s funeral wearing a face mask and socially distanced from her family at Windsor Castle, in line with Covid restrictions.
The Prime Minister’s spokesman said Boris Johnson was at his country residence Chequers on April 16 and had not been invited to the events.
Watch: Keir Starmer calls for Prime Minister's resignation over lockdown party