I don’t know. But it doesn’t necessarily have to mean that. It could be that they’ve reached a dead end and thought that revealing the video/photos might lead to new possibilities.
One thing people have been very slow to understand about the IRI and it’s hostages/kidnap victims.....keeping quiet about it is the worse thing you can do. The more noise & publicity it gets, the better the chances are that the victim will be returned and sooner rather than later.
This is true of most international hostage situations - but seems uniquely more so with Iranians. Odd.