Styling of GK Slide Appearance - no border, image flush

I would like to use the Photoslide GK3 but have just several large images, showing one at a time that would span the whole width of the slideshow area that you see on MyStore demo.

I want to remove the white margin on all sides so the image appears to float fully across the span. I'm not sure if we want to include the navigation buttons or not at this point. It will depend on how it looks with the graphics we create. If we don't use the navigation, we would want the image to have no border on the bottom then.

Can this be done? I've looked in the various css files but haven't had any luck locating the right spot to edit.

If anyone out there knows how, I'd be most grateful for the details on how to make this style change happen. Also, if it can be accomplished, where may I determine what the full width dimensions on the photos should be to fill this area?

Thanks in advance for any and all help!