centering slides in blank pages

Does anyone know what file I need to modify so that when a slide opens in a blank page it is centered? The only browser that seems to center the images is Firefox. When I examine the element, it looks like it is automatically using some sort of Google skin. However, neither Google Chrome nor Internet Explorer, center the image. It opens up way to the left. I’ve been creating custom pages and inserting the URLs as a fix, but it becomes labor intensive to create a page for each image in my slideshows. It is probably a simple fix. I’m just having trouble finding the code.

http://wordpress.org/extend/plugins/slideshow-jquery-image-gallery/