Hi
Jeremmy,
Thank you for asking. I just want to make sure we are in the same page of the issue. Settings>Themes & wallpapers>Wallpaper slideshow>My local list "add"> Gallery, and choose your pictures.
Have you turn off the "Default list" or other package that you don't want to appear?
Furthermore, please update your ASUS Launcher to the latest version. If the situation remain, could you provide me the screenshot of "Wallpaper slideshow" or any video of the issue?