Can failed iMessage pictures send automatically when conversation is delete form iPhone?

I Recently was lucky enough to put my phone on airplane modes before the wrong pictures got sent to the wrong person. The little read "!" Is right next to it. I have been worried sick thinking maybe it's going to send automatically to the person, and I'm scared to delete it myself that it might send by itself. Can I delete th converstation And not be scared of the pictures sending at the same time? Or should I just keep it my my messages?