Lightbox 2 keeps getting bigger

Question

I've implemented Lightbox 2 in my website, but I noticed a bug. The lightbox keeps getting bigger as I change pictures. After a while it looks like this:

I'm unfortunately not knowledgeable enough of JS, so I can't fix the code myself.

Answer 1

Turns out there was some of my own css interfering with lightbox.

This element caused the issue:

img
{
    min-height: 100%;
    width: auto;
}