I am trying to use this lightbox,
http://lokeshdhakar.com/projects/lightbox2/#getting-started in my app.
1) How can I add my own <div> into this source?
2) My div is consisting of several images with of different dimensions?
3) Can we customise this lightbox with my own div?
Edit: Ok let me answer your questions first. With the plugin (the lightbox made by Lokesh Dhakar),
1) No, you can't add you own div in it as it will only contain img wrapped inside the lightbox container.
2) This is ok if you wrap your images inside a div (not the lightbox when the image's triggered).
3) Yes, if you know how to tweak the original source with your own styles. So I guess you are trying to make a slideshow using lightbox with your own design.
I suggest Colorbox instead as the plugin support inline HTML. You can check them here.
http://www.jacklmoore.com/colorbox/