The image is of one of the three men who went into the bank on Lower Northam Road after a Vauxhall Astra drove into the side of the building.
Once inside the three men, who were all white, wearing dark clothing and balaclavas, stole cash from behind the till.
They were inside the bank for a short time before they all left and were seen to get into a white Audi A3, leaving the Vauxhall Astra at the scene.
The white Audi had a 15 plate and left in the direction of the roundabout at the end of Lower Northam Road.
The incident happened just before 10.30am on Wednesday.
Detective Constable Steve Roman said: “If you recognise this man or think that you saw him in the area on the day of the robbery we want you to contact us.
“You could hold vital information that could assist us with this investigation.”
Yesterday, officers released a CCTV image of the two cars heading towards the bank and a photograph of a steel beer barrel which was left at the scene.
Police have confirmed that they recovered the white Audi in Havendale, Hedge End on Thursday night. The Audi was reported stolen in September last year in Liverpool.
Do you recognise him?
Call Hampshire Police on 101 with any information