Yuri Malev was charged over posts in which he was alleged to have denigrated the St George's ribbon, a symbol of Russian military valour. One contained obscene language and the other showed a picture of a corpse wearing the ribbon.
The court service said this showed disrespect for society and insulted the memory of the Great Patriotic War, as Russians refer to World War Two.
The statement said Malev, who was detained in St. Petersburg on Friday, had "partially admitted guilt", but did not elaborate. He was placed in custody until Feb. 7.
Last week, a Russian court extended the pre-trial detention of Russian-American journalist Alsu Kurmasheva, charged with failing to register as a "foreign agent", an offence that carries up to five years in prison.
(Reporting by Reuters, editing by Mark Trevelyan)