Referenced Files in HTML

When viewing html files in full visual mode, access to any referenced files within the html file is required.
This is important for the visual editor as images used in the html file are typically externally referenced files.
There are a number of mechanisms for resolving paths to these referenced files.

If the files are referenced with absolute paths, then those locations are searched.
This includes both full URLs to web locations and local absolute paths

If the files are referenced with relative paths, then 
  firstly the files are searched relative to where the html was inserted from
  if the files are not found, this HtmlRoot folder is then searched

You can copy referenced images into HtmlRoot folder to achieve a full visual view for html files.

