Police in the North say they believe a photo appearing to show a person dressed as a Hamas fighter is fake.
The image appeared on social media earlier this week, and there were fears it could be an offence under the terrorism act.
PSNI officers have carried out enquiries, including checking CCTV from an area of Derry.
Officers “remain open minded” but have also said this situation is a “timely reminder” that not everything on the internet is as it may seem.