I have this line on my category.php page to pull up the assigned thumbnails of my post:
<div id="singleimg"><?php the_post_thumbnail('custom-thumbnail-size'); ?> </div>
What I'd like to do is allow the user to click on the thumbnail and for the main image in the post to open in Lightbox2. The post only contains an image, no text, as this is a a photography blog. The thumbnails are different sized and shaped images to the main post image so it's not possible to use the main image as my thumbnail.