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.
Dame Elizabeth Butler-Sloss, of the High Court Family Division, made an unprecedented court order banning publication of any information which could lead to the revelation of their new identities.
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 spokesman for the Attorney General’s Office said: “The AGO has been alerted to a possible contempt of court. We are liaising with the MoJ (Ministry of Justice) and others to establish the facts.
“We can neither confirm nor deny whether the pictures in question are of Jon Venables. It should be noted, there is a worldwide injunction in place which prevents the publication of any images or information purporting to identify anyone as Jon Venables.”
Venables and Thompson abducted James from the Bootle Strand shopping centre in Merseyside before torturing and killing him.
The 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.