About Loading random movies tutorial

In the [color=Red]Loading random movies tutorial[/color] we make an array specifying each movie that can be randomly picked and loaded. Works well if there are only three movies to choose from.

But what if there are for example hundreds of images or movies you want them to be randomly loaded? Is there a way to not specify each element in the array but to tell the array to find the elements in a specified folder containing all the images and movies?

I would like to make an interface where on the button release 3 random images would get displayed. The library will get increased in size over time so it would be nice that the code could include all the files in the image folder, no matter what and when i add something.

Thank you for your help,