Version:            (using KDE KDE 3.4.0)
Installed from:    Slackware Packages
OS:                Linux

X-Face support in kmail is great, but X-Face is old. The newer "Face" still is 48x48 pixels, but is encoded in PNG and supports color. More information:

http://quimby.gnus.org/circus/face/

There is an Thunderbird extension which supports Face, but not X-Face (because the author considers Face to be too slow)

http://tecwizards.de/mozilla/messagefaces/

Because kmail already supports X-Face, it looks like adding support fot the newer Face header should not be too difficult.

For compatability, kmail should support both, and both headers must be added to outgoing email. PNG Faces should be converted to X-Face if no X-Face is specified. Incoming email viewing should prefer Faces over X-Faces.