OpenGG

Simple and small lightbox clone, Modded from Joel Vardy’s lightbox, more info at http://blog.ilooker.tk/
Download and install, that’s all you need to do. And when you post articles with images, this plugin (the js script actually) will automatically lightbox those unlinked images (would not affect those images with links).
For example, I posted an article, with two image unlinked to anything (let’s call them image1 and image2), one image linked to another webpage (called image3). Then when someone click on these three images, image1 and image2 will be lightboxed but image3 will not.
Demos: 
<a href="https://jquery-littlebox-for-wp.googlecode.com/svn/trunk/demo.htm" title="Demo on Googlecode" rel="nofollow ugc">Demo on Googlecode</a> 
<a href="http://blog.ilooker.tk/" title="My blog" rel="nofollow ugc">My blog</a>
<h3>Issue list</h3>
<ul>
<li>Large image overflowing issue;</li>
<li>Iframes and flash objects unsupported yet;</li>
<li>Image groups unsupported yet (one click one image, no prev/next);</li>
<li>Not so customizable for users yet;</li>
<li>UI design improving needed.</li>
</ul>

jQuery Littlebox for WP

Simple and small lightbox clone, Modded from Joel Vardy's lightbox, more info at http://blog.ilooker.tk/

shoaib

Add lazy loading to your website and that will make your websites faster and your images will be load as after your website get load.

jQuery Littlebox for WP vs WP jQuery Lazy Load