Okay, now I'm not so sure Lightview caused the problem. All I know is that after loading Lightview (among other plugins) I couldn't access Wordpress or any pages (I got the error where a window pops open asking if I want to save index.php etc.). I thought Lightview was to blame, because all my other plugins are very tame. But maybe I was wrong. It was VERY late and I was tired. Sorry.
I lamely reinstalled the entire blog because I didn't have any content loaded anyway. Then I backed everything up and tried Lightview again. It worked and I didn't get a PHP error, but by that time I had learned about image.php and decided I prefered simple over flashy.
So I disabled Lightview. BUT then, when clicking on a gallery thumb, it opened directly to the image, rather than opening in image.php. Strange. It seems to me that Lightview altered some setting that wasn't switched back when I disabled it.
Rather than messing around trying to figure out what happened, I reinstalled Wordpress again, uploaded the backed up database, and moved on.