exclude a directory from X.509 client authentication

[ssn at ebi.ac.uk]

Hi

Please can get I some advice how to reconfigure tomcat to not enable 
X.509 client authentication on a specific directory (if possible?), when 
our IdP is selected a user's web browser might pop up a message asking 
for the user's client certificate even though the user hasn't yet chosen 
any IdP to login. This happens because the web browser fetches our logos 
from https://idp.ebi.ac.uk 
(https://idp.ebi.ac.uk/images/EMBL_EBI_logo_95x30.png) - If there is 
away to exclude the directory from X.509 authentication this should 
solve this issue.

Any further clarification please let me know.

Thanks