[Mediawiki-l] Problem with Squid : purge request latency

[Ouroboros]

Hi

I have a problem with the purge request from MediaWiki :
when it send a request to purge an image, there is a big delay (~1 seconde per
image on a page oO), I have checked my Apache & Squid logs and I have found that
MediaWiki try to purge a thumb of each image... but the thumb doesn't exist.
I think (not sure) my problem come from the latency caused by the 404 error...
but I don't know how to resolve this. Have you an idea?

Squid log example (purge request for a 64x64px image - not rescale):

xxx.xxx.xxx.xxx - - [27/May/2007:09:56:47 +0200] "PURGE
http://mydomain.tld/w/images/thumb/7/7b/Image.png/64px-Image.png HTTP/1.0" 404
109 TCP_MISS:NONE


PS: sorry my english is bad - I'm french ^^