Any update on this? I am using Moodle 2.0.7 (Build: 20120109) and whenever someone posts a picture on the forum, it is not displayed on the emails.
MDL-25944 has been closed (resolved) 2 years ago. It should have been re-opened if problem was not corrected.
But now, Moodle 2.0 is outdated, and no more updated. You should really update to Moodle 2.2 (first), and perhaps then to 2.3 or 2.4.