White bars by Lightbox

Hello,

I have the free version of the plugin. I like to use the lightbox option.
My pictures are 1024×768, I have set this by the setting. But if I click on a picture. I see White bars.

I see white bars above and below my pictures. Is this an setting? So I can remove these beams as well?

The page I need help with: [log in to see the link]