Venables was 10 when he and classmate Robert Thompson abducted and murdered two-year-old James Bulger in Liverpool in Feb 1993.
Thompson and Venables were jailed for life but released on licence with new identities in 2001.
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.”
James Bulger’s mother, Denise Fergus, has made no comment about the alleged breach.
Fergus, 45, has always opposed the injunction, fearing it could lead to innocent men being accused of being James’s killers.
Venables and Thompson abducted James from the Bootle Strand shopping centre in Merseyside before torturing and killing him.
Niri Shan, of law firm Taylor Wessing, suggested the attorney general should use the case to send a message.
“As highlighted by (Director of Public Prosecutions) Kier Starmer’s recent guidelines on social media, people are subject to the same laws of contempt as the mainstream media and publishing a photo of Venables, in breach of the court order, is clearly contempt of court.
“This would be a good case for him to send a strong message to those that use Twitter that they breach court orders at their own peril.”