Apache Reference: mod_autoindex, AddAlt
Alternative Text for File Icon
Syntax: AddAlt text file [file ...]
Example: AddAlt "TGZ" *.tar.gz
Since: Apache 1.0
This directive sets (one or more times) the alternative text to display for a file - instead of an icon, for FancyIndexing. The file argument can contain a file extension, partial file name, wildcard expression, or full file name. The text argument consists of a string enclosed in double quotes. This alternative text is displayed if the client cannot show the image or has image loading disabled.