This sets the icon to display next to files of type MIME-type for FancyIndexing. Icon is either a (%-escaped) relative URL to the icon, or of the format (alttext,url) where alttext is the text tag given for an icon for non-graphical browsers.
Mime-type is a wildcard expression matching required the mime types. Examples:
AddIconByType (IMG,/icons/image.xbm)
image/*