From the site:
Slimbox 2 is a 4 KB visual clone of the popularLightbox 2 script by Lokesh Dhakar, written using the jQuery javascript library. It was designed to be very small, efficient, standards-friendly, fully customizable, more convenient and 100% compatible with the original Lightbox 2.I like it, it works well and is pretty easy to set up. I hosted the JS files in my Google Drive so all is sweet.
I followed this helpful guide to put things in the right place. For the bit where you have to specify where the slimbox js files reside I used this post to host the code in my own Google Drive.