CanadaRAM hit most of the main points there. This is something a lot of people have to deal with when they let WYSIWYG editors like Dreamweaver write code for them. If you're making a static site, then the best way to reference your images is to use relative paths. That is, relative to the document you're calling them from. For example, say you have a site structure like this:
Code:
[b]site/[/b]
[b]css/[/b]
main.css
[b]downloads/[/b]
fileList.html
[b]images/[/b]
banner.jpg
button.gif
picture.jpg
index.html
You want to reference an image from index.html; your img tag would look like this:
HTML:
<img src="images/banner.jpg" alt="Some title">
If you were referencing an image from downloads/fileList.html, it would look like this:
HTML:
<img src="../images/picture.jpg" alt="Pretty picture">
That double dot means "go up one directory". You would use the same path if you were referencing images from the main.css file in this example.
The point is, if you build all your image paths (and internal href links) like that then you can move the site anywhere and it will always work without any modification. Now, if you're building a dynamic site using PHP or something there's a much better strategy, but it doesn't sound like you're doing that.
