The Attorney General has decided to bring contempt proceedings against individuals who posted photographs online purporting to show James Bulger killers Jon Venables or Robert Thompson.
Venables was 10 when he and classmate Robert Thompson abducted and murdered two-year-old James Bulger in Liverpool in February 1993.
Thompson and Venables were jailed for life but released on licence with new identities in 2001.
Venables, now 30, had his parole revoked in 2010 and was jailed for two years after admitting downloading and distributing indecent images of children.
The images, which appeared on the social network site Twitter, claimed to show an adult Venables posing with friends. The Twitter user has since removed the posts.
A statement from the Attorney General's office read: "There is an injunction in place which prevents publication of any images or information purporting to identify anyone as Jon Venables or Robert Thompson.
"The terms of the order mean that if a picture claims to be of Venables or Thompson, even if it is not actually them, there will be a breach of the order. Providing details of the new identities of Venables and Thompson or their whereabouts is also prohibited – this order applies to material which is on the internet."
The statement also warned against the potential danger of wrongly identifying innocent men, continuing: "There are many different images circulating online claiming to be of Venables or Thompson; potentially innocent individuals may be wrongly identified as being one of the two men and placed in danger. The order, and its enforcement, is therefore intended to protect not only Venables and Thompson but also those members of the public who have been incorrectly identified as being one of the two men."
Venables and Thompson abducted James from the Bootle Strand shopping centre in Merseyside before torturing and killing him.
The two boys, who were truanting from school, walked James around the streets of Liverpool for more than two miles, stopping occasionally to kick and punch him.
They told adults who intervened that he was their brother.
After taking him to a nearby railway line, they left his body on the tracks in the hope it would be destroyed by a train.
The toddler had been splattered with blue paint and his battered head lay surrounded by a pile of bricks.
His body was found two days later by children playing on a freight railway line.