I've found when you go "Settings" > "View" > "Misc." > "Quick slideshow" > "Direction: Random" in XnViewMP you can get the slideshow to switch to a random picture. However the order of the pictures is always the same.
Let's say the folder contains the pictures A, B, C, D. Then it could be random, e.g. D, A, C, B. But no matter where you start, where you scroll to, whether you stop and start it, the order seems to be always exactly like this.
I assume the random number generator is simply seeded always with the same value (none?), where one could use something that changes everytime e.g. the current timestamp.
I don't know if this is useful behavior for someone, but I'd consider this behavior a bug, as the direction is no longer random for me when I have watched a set of pictures in that 'random' mode for several times.
Hope I've helped.
