Ok..after fideling around with the phone, I figured out that you can not do this on this model of phone. You can not set up a slide show as a charging screen or a wallpaper like you can on the LG Dare. Why they would remove this feature I do not know? Maybe it wasted too much of the battery power having the screen on all the time. what you can do however is when you are in your pictures, and have one of your pic's selected you can hit the options button on the upper right hand cornor and then select slideshow and you can see a slideshow of your pictures this way.
There is no setting for that option. But you can goto Menu then Media Center then select pic & video then My pic then select any photo then the drop down symbol on the top right corner from the external screen then select slide show. Now, if you open your phn to the key board you still able to see the slide show however, it goes to the main screen when you close the phn. ☹️ Over all its better then sliding it yourself. 🙂