The picture, apparently a still taken from a video, showed six sailors sitting in blue and red tracksuits on a carpet in a room. What appears to be a little bowl of nuts stands in the middle of the group.
The caption to the picture says: "British sailors are chatting and eating fruit, drinking coffee and playing chess. It seems that the sailors are satisfied with their situation, in which they are enjoying good conditions instead of working in a hard situation in the Persian Gulf."
The picture included the only female member of the 15 sailors seized by Iran in the Gulf on March 23, Leading Seaman Faye Turney.
On Monday, an Iranian state media said they would not be broadcasting any more video confessions of the sailors because of what they called "positive changes" in the negotiating stance of Britain, whose government has condemned the airing of videos of the captives.