Design Problems With Net Accelerators

I had a client call me today and after putting Netscape Accelerator on her computer, her site looks absolutely hideous when she views it. I had no idea what she was talking about. Her site looked fine to me on my computer and on the other computers in my shop. Even in different browsers it looked the same. So I went to her shop to see what she was talking about. She was right. The graphics I designed for the site and most of the pictures are TERRIBLE. Even some of the javascripts don't work on her site when she views it. Is there any information available about getting around the accelerators so they can't do that to the pages I design? Any information would be greatly appreciated.