[evolution] User docs: Clarify automatic X-Face display as per bug 698435

[Andre Klapper <aklapper src gnome org>]

commit 513789838df36eb201187f05835591ef680ca181
Author: Andre Klapper <a9016009 gmx de>
Date:   Sat Apr 20 15:43:58 2013 +0200

    User docs: Clarify automatic X-Face display as per bug 698435

 help/C/mail-displaying-sender-photograph.page | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/help/C/mail-displaying-sender-photograph.page b/help/C/mail-displaying-sender-photograph.page
index b956350..8702c63 100644
--- a/help/C/mail-displaying-sender-photograph.page
+++ b/help/C/mail-displaying-sender-photograph.page
@@ -22,7 +22,11 @@
 
 <title>Photograph Message Headers</title>
 
-<p>The photograph of the sender of an email can be shown at the right side of the message preview if the 
sender is in one of your address books and has a photograph.</p>
+<!-- NB: This is done by "Face" and "X-Face" headers. -->
+<p>Evolution automatically displays photographs of the sender of an email at the right side of the message 
header if the sender already embedded a photograph in the message.</p>
+<!-- TODO: If I ever manage to find out if the "Edit > Plugins > Face" reliably works, create a topic page 
covering it linked under <link type="guide" xref="index#mail-composing-advanced" />, and link to it from here 
and vice versa. -->
+
+<p>You can also manually enable displaying the photograph of the sender of an email if the sender is in one 
of your address books and has a photograph stored.</p>
 
 <p>To enable this functionality, select <guiseq><gui>Edit</gui><gui>Preferences</gui><gui>Mail 
Preferences</gui><gui>Headers</gui><gui>Show the photograph of sender in the message 
preview</gui></guiseq>.</p>