North Yorkshire Police say it happened in St Thomas Street in Scarborough at about 3.12am in the early hours of January 28.
A police spokesman said: “The victim was taken to hospital with a serious head injury.
“Officers are asking members of the public to get in touch if they recognise the man in the images as they believe he will have information that will help the investigation.”
Anyone with any information is asked to email emily.myers@northyorkshire.police.uk or call North Yorkshire Police on 101, select option 2 and ask for Emily Myers.
If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111.
Please quote reference number 12240016729 when passing on information.
