Last night I got somebody on chat and due to some confusion I sent one of a very personal pic to both those people. Can that pic be deleted from their phones?
No, you can't delete pics from other people's phone. So you need to think twice before doing this. Don't let out your personal pics to otheres especially unknown ones.
You can, if you delete the picture from the chat screen of yours, till the time, it is not delivered to the other person, as it remains on chat scripts till you remove it.
Unfortunately, it can't. Once the picture is delivered, there is no way to remove it without the user's approval. I am afraid that the only way to do it now is to ask the users to delete the item.