I'm using a number larger then the slide total for the 'first image index', so I don't get a slide displayed until you click on a thumbnail.  The first slide appears fine, when you click a thumbnail.  However, when you click a different thumbnail, the first slide stays there, behind the next one (showing round it if the second slide is smaller or a different orientation).  That first slide then remains throughout any further transitions, unless you click on the first thumbnail again, in which case it starts behaving properly, and disappearing as it should.  So how do I sort this out?