Scrolling through gallery pictures

Hi, I have set up a few galleries on my site with arrows to scroll through the images. However some go through from first to last by clicking the right hand arrow then you have to go back by clicking the left hand arrow whilst others go through continuously by clicking the right arrow (which I prefer). What is it that is making the difference, as far as I can see they are all set up the same?

Please ignore my incompetence - I thought I had set up wrap around on them all but hadn’t!