How to reach it
In Games & Emulation Main Screen open the context menu (right click) of the image viewer (top right corner) and choose the Open Viewer Settings menu item.
How it works
Here you can define how and in which order the image viewer in Games & Emulation Main Screen should display USER Extras.
Enable/Disable the Slideshow mode by checking/unchecking the Slideshow checkbox. Define a delay in seconds for the slideshow.
Decide, which USER Extras categories should be displayed using the Hide checkboxes.
Re-arrange the order by using the Move Up and Move Down buttons.