Enable the "default|d" query string parameter using mod_rewrite
Enable the "default|d" query string parameter using mod_rewrite

This default image URL is used instead of the nobody image and is passed
along to gravatar when we delegate to them.

The Gravatar special values of mm, identicon, monsterid and wavatar are
stripped out by Libravatar, but "404" is supported.

libravatar/libravatar,libravatar/libravatar,libravatar/libravatar,libravatar/libravatar,libravatar/libravatar,libravatar/libravatar,libravatar/libravatar