Apache2 Conditional Logging help

[Colin J. Raven]

I'm trying to supress logging of such things as favicon.ico, gifs and 
jpegs. In a home server environment (right now anyway) I just don't 
think it's necessary to log serving of those items.

Accordingly, some googling seemed to point me towards doing something 
like this:
########################################
SetEnvIf Request_URI "\.gif$" dontlog
SetEnvIf Request_URI "\.jpg$" dontlog
SetEnvIf Request_URI "\.jpeg$" dontlog

But this doesn't work - at all. Images are still being logged
My images are in /path/to/web_data/images, so perhaps that has something 
to do with it. I can't figure out the syntax to accomplish calling the 
path proerly though. Various kinds of fiddling with the syntax and 
restarting httpd hasn't worked.

Part of the problem is that apachectl configtest doesn't complain about 
syntax no matter how I fiddle with any of these. It just reports "Syntax 
OK" and when I restart there are no logfile errors.

########################################
# This one shuts down *all* (access) logging, which is truly puzzling:

# SetEnvIf Request_URI "\.gif$" object_is_image=gif dontlog
# SetEnvIf Request_URI "\.jpg$" object_is_image=jpg dontlog


Some help would definitely be appreciated!!

Regards & TIA,
-Colin