Slideshow mode
[gallery mode="slideshow" width="3" height="2" ids="0001,0002,0003,0004…n"]
Default mode
[gallery columns="1 / 2 / 3 / 4 / 5 / 6…" link="file" ids="0001,0002,0003,0004…n"]
[gallery mode="slideshow" width="3" height="2" ids="0001,0002,0003,0004…n"]