The victim, a 22-year-old man, was enjoying a night out with a friend in Harrogate town centre, when he was approached by a couple on Cheltenham Parade at around 3am on Saturday 29 June 2013.
They began kicking him and as he defended himself, he sustained a broken bone in his right arm.
Officers are investigating the incident and are appealing to anyone who recognises the people pictured to get in touch.
Anyone who can help officers with their enquiries is urged to contact North Yorkshire Police on 101 – select option 2 – and ask for PC Amy Hunter or Harrogate police.
Alternatively, information can be emailed to email@example.com
If you wish to remain anonymous, Crimestoppers can be contacted on 0800 555 111.
Please quote reference number 12130106383 when passing information about this incident.