[Mediawiki-l] logo oddity

[Martin Smith]

I have set up a test server and yesterday installed 1.15.0 and got it up 
and running, no problem there.
However I have added a logo $wgLogo = "images/courgette.png" the logo is 
the right size, again no problem but on entering the site at the main 
page no logo is visible, however when I click on log in and go to the 
log in page the logo suddenly appears, after logging in it vanishes 
again. If I create a new page, the logo is visible when I edit the page, 
but vanishes after saving.
I have tried this from a couple of different machines with a couple of 
different browsers and there is no change in the behaviour.
If I comment out the logo statement the default change this logo appears 
on every page, I have also tried moving the statement to different 
places in LocalSettings.php but that (obviously) does not help.
Any useful comment would be appreciated, thanks
-- 
Martin