The 76 year-old was approached from behind while walking onto the Greenway in Cleckheaton and hit on the back of the head with a hammer by the suspect who then made off with her purse.
She was taken to hospital for treatment and was released last week.
The suspect is described as a white man, slim, aged around 60, wearing a woolly bobble hat and glasses.ã€€
Det Con Kris Roberts, of Kirklees CID, said: "We are continuing our investigation to locate the man responsible for this serious offence and would like to speak to anyone who has any further information or who can identify the man in the picture."
Contact Kirklees CID on 101 referencing crime number 13170207307 and information can also be passed to Crimestoppers anonymously on 0800 555 111."