I think I may have fixed this problem by playing about with cache settings.
1. Joomla Site Global Configuration: Cache to "On - Progressive".
2. Joomla Plug=in Manager, ARI Extensions: Fix Cache Issue to "Yes".
IE9, Firefox, Safari and Google Chrome all display the slide show with the slight proviso that Safari "stutters" a bit on the image transition.
Also, Jooma Site Global Config, Cache to "Off" also works but all the browsers "stutter" on the image transition; Cache to "On - Conservative" (the original setting) produces the failure to load the slide show.
Many thanks.
I now have another problem! None of the browers will display the slide show after being closed and reloaded unless I perform "Site, Maintenance, Clear Cache" in the Joomla backend and then hit "CTRL & F5" in the browser - this applies to all four browsers that I've tested Photo Gallery on; merely hitting CTRL & F5 in the browser is not enough. Its a bit difficult to describe what actually happens when I click on an image. What happens depends on the browser. They all appear to start attempting to display the slide show, the lightbox begins to open (in a different spot on the screen depending upon which browser I'm using) and then shoots up the screen, vanishes and the screen opacity clears like a blind coming down the screen.
