My girlfriend's Messenger in Facebook has a message that contains photos but has "just you" next to it instead of the person's name. I didn't open the message but could see that it contained 24 pictures. Why would it have this name or phrase next to it?
"Just You" means that someone has messaged themselves in a chat conversation. It can be used to keep things for reference.
I used to message myself on Facebook to send links to my computer from my iPod Touch, but apparently your girlfriend used it to share pictures with herself.
Just You means exactly what is says. You can message this "Just You" and the messages will be kept between you and that account. Uhmm.. basically its your own account that you can message.