Well... I got this one working. Basically you make changes to: forumdisplay.php and showthread.php just like you make changes to the index.php file and then the code in your FORUMDISPLAY and/or SHOWTHREAD templates:
<if condition="$foruminfo[forumid] == 24"> $photopostfeature </if>
(24 is the forum ID)
Works great,
demo here