This post is mainly for Jerome and Dong
The current webservices for displaying information about an user returns a value called:
user.profileimageurl
This is the full url of the user profile image
Please, note that the current implementation only works if forcelogin is set to NO and guestaccess to Yes
Also, there is a new security issue for preventing displaying profile images for guests users
http://tracker.moodle.org/browse/MDL-29844
I think it's neccesary a new script for obtaining this image using the auth token as a parmether (like the new pluginfile)