This template will randomize the Slideshow images on page load. This was create as a template so that it can be applied to individual themes and not the whole store. Although it can be applied to the whole store by replacing the slideshow.tpl file in the default theme.

The default theme location would be: catalog\view\theme\default\template\module

Before replacing any template or module, rename the original to .bak (if present) then copy the new .tpl/.php file to the location. this is to provide you a backup so that if you don't like the new files operation you can just delete the new file then rename the .bak file to the original file name.

This was done using the code from http://www.soslignes-ecrivain-public.fr/Convert-Nivo-slider-to-a-random-slideshow.html