Here you can change slideshow Mode, paging, sorting and many more..
Navigate to Manage -> Basic
Slideshow: Appears when LightBox Effect is set to 'Enabled'
Enable Slideshow: (Default: Disable)
If enabled, creates the Slideshow controls (Next, Previous, Play, Move and Close)
Repeat: (Default: disable)
If selected it repeats (loops) through after last slide.
Interval: (Default: 5000)
Sets the duration for which each slide is shown before transition