A woman went to the self-service checkout at Asda in Bower Road and left without paying for two items.
The theft took place at around 9.50am on Saturday, July 29.
Issuing a public appeal, a police spokesman said: "If you recognise the woman in the CCTV image, or have any information which could assist the investigation, please contact North Yorkshire Police."
Email [email protected] or dial 101, select option 2, and ask for PC 1972 Matthew Reeve.
Alternatively, Crimestoppers can be contacted anonymously on 0800 555 111.
Please quote reference number 12170133569 when passing on any information.