The slideshow consists of the slides that are shown for a certain time before the slideshow moves on and transitions to the next slide. In Endless Slideshow Screensaver this time, which is called the [ Viewer timing ] can vary from seconds to hours and does not have to be constant for every slide. You can find and modify it in the Endless Slideshow Screensaver settings, [ Viewer ] tab, [ Timing ] section:
If you want a constant period of time for every slide, then set the same values in the [ From ] and [ To ] fields. Those fields represent the minimum and maximum number of seconds, minutes, or hours every slide is shown. If you set different values in those fields - Endless Slideshow Screensaver will use a random number from the given interval (including both [ From ] and [ To ] values) for every slide.