Robert Wilson, 36, of Dame Dorothy Crescent, Sunderland, also allegedly told the woman in a voice message, “I’m coming to yours with a gun”.
And in a further alleged communication, South Tyneside Magistrates’ Court was told he sent a message to her on the social media site saying, “I’m going to blow your ******* brains out”.
The court heard Wilson and the woman were not known to each other but had become linked via the social media messaging system.
When she posted she had a bed for sale, Wilson got in touch and said he would like it and made arrangements to collect it.
The court heard the posting of the image and the alleged threats came after she changed her mind and messaged him to say she had decided to give the item to a friend.
Magistrates were also told the alleged messages made the woman stay away from her home for fear of reprisals.
Wilson admitted sending the photo on January 6 and pleaded guilty to a charge of sending a letter, communication or article which could cause distress of anxiety.
But he denied threatening the woman in a voice call and sending a threatening Facebook Messenger message, admitting only to the photo.
Wilson was granted conditional bail as District Judge Paul Currer said the issues around the allegations must be decided at a later hearing, at Gateshead Magistrates’ Court on May 26.
Prosecutor Lorna Rimell said: “She had seen that the defendant had added her as a friend some time before, she didn’t know who he was.
“She put on an advert about a bed and he got in touch and made arrangements that he would come and collect it, but she subsequently decided to give it to a friend.”
Charlie Carr, defending Wilson, said: “He got himself rather annoyed because he’d made arrangements to collect the bed. He got himself awfully upset, it was a spur of the moment thing.”