How to send bitmap to application?

[Josef Hajas]

Hello, I'm developing pam_bioapi and have this problem: I can receive
from driver of biometrics sensor bitmap representing actual state of
device and I want to send this bitmap to application. Ok, I can use
pam_conv, but what if application don't counting with possibility that
incoming data isn't string but picture? Is there any other standard
way how to send to application picture from pam module and do it in
way that application have option to show this picture, but if there
isn't support for this at application side it just don't be necessary?

Thank you for your suggestions

Josef Hajas