I do not know the specific image you are talking about but could it be this one?
From: FreeSWITCH-users <freeswitch-users-bounces@lists.freeswitch.org>
On Behalf Of David Villasmil
Sent: Friday, December 28, 2018 1:12 PM
To: FreeSWITCH Users Help <freeswitch-users@lists.freeswitch.org>
Subject: [Freeswitch-users] Module's architecture image
Hello all,
Years ago, Anthony sent out an image explaining FS' module architecture. I had it somewhere but can't find it now...
Anyone got it?