Gravatars

I want to put some icons in a web and I want to know how can I detect
if a person has a gravatar so in case they don't have one I want to
show another icon, can anyone help me??
Thanks in advance
Belén

I tried a while ago to implement this and finished doing a column in
the users table saying wants_gravatar:boolean. If it was true, then
the user.face method would return their gravatar picture like so:

  if wants_gravatar?
      "http://www.gravatar.com/avatar.php?
gravatar_id=#{Digest::MD5.hexdigest(email_address)}"
    else
      self.avatar ? self.avatar.public_filename : DEFAULTFACE
    end

but actually checking wether the email address mapped any pictures in
gravatar or not, i could not find a way. I decided that if the user
wanted a gravatar an didnt have one, hed just get the gravatar logo.
it was so much less painfull to implement.

It still appreciate if anyone knew how to perform the check.

j

seems there are two plugins available:
http://en.gravatar.com/site/implement/rails

but none of them seems to implement any check, if a gravatar exists
as far as I can see, the only thing possible is to set one of three
default images:

http://en.gravatar.com/site/implement/url