A young man suffered a fractured eye socket in an early-morning attack in Chesterfield.
The victim was walking along Holywell Street at about 1.15am on Friday when he was approached by another man and assaulted.
He was punched in the head and fell to the floor. He was taken to hospital by ambulance and treated for the fractured eye socket.
Police have now released these CCTV images of a man they want to speak to in connection with the incident.
If you recognise him, call Derbyshire police on 101 or Crimestoppers on 0800 555 111.