If your slideshow contains many slides and you want to see more thumbnails at the same time, use light table view. You can easily reorder slides by dragging, as if the slides were spread out on a photographer’s light table.
To show light table view, click View in the toolbar and choose Light Table (or choose View > Light Table).
To enlarge or shrink the thumbnail images, click the button in the lower left of the window and choose a size.
To edit a slide or return to your previous view (navigator or outline), double-click a slide.
In light table view, you can add, delete, duplicate, skip, and reorder slides just as you can in navigator and outline views.