Have tried multiple ways of fixing a problem with this plugin that does not load correctly. The length of time allowed after the initial page load makes no difference - whether the page has loaded for 1 second or 15 seconds: the first image that is clicked on, not necessarily the first in the gallery, loads as a normal /imagename.jpg page. Then when the visitor clicks "back" then reloads the same image, the lightbox plugin "kicks-in" and works. It is as though an image needs to be clicked on to activate the plugin on the page. Other than that, everything works fine and looks beautiful.
Tried the following:
Smush.it plugin for all images, thinking they were too large;
Plugin Organizer plugin and ordered jQuery Lightbox plugin to load first;
Used W3TC to clear all page caches.
None of these seem to do the job.