Mr Steadman was suspended as a Labour member after the party was notified of his arrest in June 2024.
He resigned as a councillor in Islington, north London the following month.
Malcolm McHaffie, head of the Crown Prosecution Service’s Special Crime Division, said: “We have decided to prosecute Oliver Steadman with blackmail and five communications offences in relation to a total of five victims working within politics and Westminster.
“This follows an investigation by the Metropolitan Police Service which looked into messages that included alleged unsolicited indecent images sent to a number of people within parliamentary political circles between October 2023 and April 2024 using Whatsapp.
“Our prosecutors have worked to establish that there is sufficient evidence to bring this case to court and that it is in the public interest to pursue criminal proceedings.”
Mr Steadman will appear at Westminster Magistrates’ Court on 3 November.