when you rip an HTML page straight off a site all your doing is taking the source code - not the images associated with the page. If the images used on the page are referenced locally IE. the full path names arn't given, when you reload that page from your hard drive the images/URLs are pointing to the wrong location.
There are 3rd party tools with more functionality saving web pages but I can't recommend any specific one because I don't use them. Alternatively if you just wish to view web pages offline there is an option available when you add it to your favourites in IE (I assume a similar option is available in Firefox also).
