How Can I Customise ImageGallery Page To Match My Site Layout

[Truegho]

I have just added the Image Gallery to my True Ghost Stories site (it came with my web package). However, I would like to customise the gallery page so that it matches the layout of my site. How do I do it? Is it very complicated?

My site has a black background layout and a ghost story logo on every page.

Thanks,
The Webmaster
www.trueghoststories.co.uk