[Users] Face header size limits

Michael Schwendt mschwendt at gmail.com
Mon Jun 24 12:56:51 CEST 2013

Hello everyone!

Occasionally, I notice people including a "Face" header for a picture
that exceeds the ancient size limits from 2005:

   | Maximum encoded header length: 998 characters 

There are email clients, which don't reject larger images and display
them completely (e.g. Evolution). In two example messages I've saved,
the encoded header is 6137 and 6299 octets long.

In Claws Mail src/gtk/gtkutils.c, there's a fixed maximum PNG size of 2048
bytes. PNG data that is cut off at that point cannot be decoded properly
and will damage the remainder of the 48x48 area (instead of decoding to 
something blank).

What do you think? Is this anything CM should try to handle, too?
If an email like that has arrived in a CM user's mailbox, the user will
likely believe Claws Mail is unable to display the "Face". Has anyone
observed users including Faces larger than let's say 8192, 16384 or
(insane) 32768 octets yet?

Fedora release 19 (Schrödinger’s Cat) - Linux 3.9.6-301.fc19.x86_64
loadavg: 0.26 0.12 0.10

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