Brian, thanks. I was aware of that css rule, but wouldn't it apply to all modules? I was trying to style just the RokSlideShow, or more specifically its container.
Regarding image sizes, I'll play with the file size/image quality to see how much they can be whittled down without diminishing the effect too much.
Reduced the images to 30-50KB each. Let me know if it helped.
I played with the CSS rule you mentioned, Brian, and it does affect other modules adversely. For example, it pushes the text in the right position module (currently "Advertisement") flush against its left margin.