CSS and/or MasterPage not showing in Debug

Have you ever known about a problem for a while, but because it wasn't interfering with the PROGRAM itself, you put it off until you HAVE to deal with it? :-)

I have a web project converted from .NET1.0/VS 2003 to .NET2.0/VS 2005. Among other conversions, I added MasterPages and style sheets. There are a couple of problems I'm having:

1. When I am debugging, the styles defined in the Style Sheets are not appearing on the screen. They show in the designer, but when I debug (OR look at it in the browser), they're gone. Doesn't change.
   
2. From time to time (oh, goody! An intermittent problem!), it will lose an image button or image. I select them using the URL finder, and sometimes they show, sometimes it takes several tries to get them to show up.But inevitably, one or two are gone during debug.

The data is not in the App_Data file. The icons are in a folder named img and the master page is in a folder named graphics. I cannot understand why it is connected in Visual Studio, but gone in the web page.

Any help is appreciated, because I'm stumped!