I am not sure if lightbox supports it. Perhaps not. For that reason i went for jquery slimbox in my project and i call it like this on a link click:
el.children("img").bind("click", function(){
jQuery("#GArticlesContainer a:has(img)").slimbox();
});
el beeing in another elment not the one thats beeing clicked. It binds GArticledcontained links that have image to open them with slimbox. You could do the same with button i guess.
If you want to see more of how it works then go check:
http://www.sanlab.ee/gallery/
If you want to open picture on link click, not just add jquery event to a new image, likein the case of sanlab, you can do that:
jQuery.slimbox(url, description, options);
Check out slimbox api about it: http://code.google.com/p/slimbox/wiki/jQueryAPI
Hope, that answers your question.
Alan.